Just to clear things up i have checked both the official Man Utd website to check the player stats and have also checked the wikipedia page as others have stated to check the player goalscoring stats and the results are as follows for each of Utd's current strikers in terms of their goals-to-game ratio for Utd and in their career in total :
Wayne 'Wazza' Rooney (1st choice striker at UTD) - Official Man Utd website stats - 365 appearances, 181 goals = 2.01 goals-per-game ratio.
Wikipedia page stats - 366 appearances, 182 goals = 2.01 goals-per-game ratio.
Club Career Stats - 443 appearances, 199 goals = 2.22 goals-per-game ratio.
Danny 'Danny Boy/Dazza' Welbeck (2nd/3rd choice striker at UTD) - Official Man Utd website stats - 63 appearances, 17 goals = 3.70 goals-per-game ratio.
Wikipedia page stats - 64 appearances, 17 goals = 3.76 goals-per-game ratio.
Club Career Stats - 98 appearances, 25 goals = 3.92 goals-per-game ratio.
Javier 'Chicharito' Hernandez (3rd/2nd choice striker at UTD) - Official Man Utd website stats - 81 appearances, 32 goals = 2.53 goals-per-game ratio.
Wikipedia page stats - 81 appearances, 32 goals = 2.53 goals-per-game ratio.
Club Career Stats - 161 appearances, 60 goals = 2.68 goals-per-game ratio.
Dimitar 'Berba' Berbatov (4th choice striker at UTD) - Official Man Utd website stats - 149 appearances, 56 goals = 2.66 goals-per-game ratio.
Wikipedia page stats - 149 appearances, 56 goals = 2.66 goals-per-game ratio.
Club Career Stats - 517 appearances, 237 goals = 2.18 goals-per-game ratio.
just for the fun of it -
Federico 'Kiko' Macheda (5th choice striker at UTD) - Official Man Utd website stats - 33 appearances, 5 goals = 6.6 goals-per-game ratio.
Wikipedia page stats - 33 appearances, 5 goals = 6.6 goals-per-game ratio.
Club Career Stats - 55 appearances, 6 goals = 9.1 goals per-game ratio.
Tiago Manuel Dias Correia a.k.a Bebe (6th choice striker at UTD as he clearly isn't a winger, much more a natural forward bursting through the middle is where he can do his damage once fully developed...if he can achieve so!) - Official Man Utd website stats - 7 appearances, 2 goals = 3.5 goals-per-game ratio.
Wikipedia page stats - 7 appearances, 2 goals = 3.5 goals-per-game ratio.
Club Career Stats - 37 appearances, 6 goals = 6.16 goals-per-game ratio.
So, according to the Official Man Utd website Wayne Rooney is Man Utd's 'best' striker in terms of goals-to-game ratio (which is the fairest way of working this all out as the strikers job at the end of the day is ultimately to get as man goals as possible for their team. This player being the most influential at doing so at United.
According to the Wikipedia page stats the results are the same.....Wayne Rooney.
Finally, according to the Club Career Stats as mentioned on the same Wikipedia page Dimitar Berbatov is Man Utd's 'best' striker in terms of goals-per-game ratio. However, to say this makes Berbatov the 'best' according to these stats i think would be unfair as he is older than all the other strikers and so has naturally played many more games than the rest an therefore of course is highly likely to have scored more goals than the others, especially as he has played for more clubs than the other striking options also.
Plus, at the end of the day we are talking about Man Utd players and we are mainly interested in how many goals our own Man Utd players can get for Manchester United and therefore the best and most sensible manner of determining which of our strikers is the 'best/most influential' FOR US in terms of their main aim - to score goals, the outcome is that Wayne Rooney emerges as that very striker at United.
Wayne Rooney's goal stats being 2 goals-per-game (2.01 according to both Official Man Utd website & Wikipedia page), then Chicharito being 2nd with a goal per 'just over every 2-and-a-half games' (2.53 according to both Official Man Utd website & Wikipedia page), then Dimitar Berbatov in 3rd with a goal per 'a bit more over 2-and-a-half games' (2.66 according to both Official Man Utd website & Wikipedia page), then Danny Welbeck next in 4th with a goal per every '3-and-3-quarter games' (3.70 according to Official Man Utd website & 3.76 according to Wikipedia page), next is Bebe with a goal every '3-and-a-half games' (3.5 according to both Official Man Utd website & Wikipedia page), and lastly Federico Macheda with a goal every 'just ever so slightly over 6-and-a-half games' (6.6 according to both Official Man Utd website & Wikipedia page).
Also worth mentioning that the Wikipedia website pages for these stats are somewhat misleading as at the top of the page (and slightly to the right) these stats are different to the stats towards the bottom of the player's profile page as the stats at the top end have NOT been updated properly/recently whereas the stats towards the bottom end of the page have been properly updated and are more in tune with the stats on the Official Man Utd website (makes more sense to go by the Official Man Utd website tbh as it is much more reliable and cannot be edited 'willy nilly' by any old 'tom, *** OR harry' and they are from the Official Man Utd staff after all who update the player profiles after each games played with appearances and goals tallies.)
Those are the stats/facts as stats are a direct reflection of the facts. Also, at the end of the day my personal opinion is that i'd prefer to keep Berbatov as our backup 4th choice striker which is where he is now and play games when the likes of Rooney, Chicharito and Welbeck are rested/injured/fatigued etc...However this looks to be highly unlikely as Berbatov will not accept this and would prefer to leave for a club where he can be guaranteed a starting place and not have to fight/earn his way up the ranks to be 2nd choice (as no-one is going to remove Rooney as 1st choice striker...and rightly so as Rooney is our key forward and can give more than all our other strikers in truth (our one true 'complete forward player').
So with it being likely Berbatov could go, that would leave Macheda taking Berbatov's 4th choice position upfront as Macheda's agent has stated that he will remain with Utd this season and not go out on loan but stay with the Utd 1st team as backup to play in the League Cup and against 'weaker' teams in the FA Cup and Premier League this coming season season. Bebe either going back on a season-long loan again as his last one was ruined through a very bad injury just in case people hadn't noticed (that's why he hasn't developed much since we last saw him in a Utd shirt as you cannot develop when you are injured for the whole season...and he has only just started playing now in pre-season, very well actually).
Hopefully he keeps it up this coming season wether it be on loan or with Utd (stay at Utd as backup and to play alongside Macheda in the League Cup and against 'weaker' in the FA Cup an maybe some game time from the bench in certain Premier League games like when we are winning comfortably and we need to give certain players minutes on the field with the senior squad.
However, if no club comes in officially to pay the asking price and Berbatov doesn't move this Summer then he himself has stated that he would remain professional and fight for his place in the Utd squad and try and get as many starts as possible, this could only be a good thing for Utd as it would be benefitial to have all our strikers competing for a starting place and giving it their all to get as many goals as they can as that is their main job and after all...goals win games! (Vidic will surely help at the back to solidify the defence and now having had full seasons under Lindegaard and De Gea's belts can only be a positive for them an Utd also.) I firmly believe you learn far more from defeat than victory and i'm confident Man Utd collectively will have 'learnt a very cruel leason' from last season's failure's and will give 100%+ to make sure we avoid similar disappointment this coming season!
P.S - Now after all this time and preparation put into this post i will post it to see the paragraphing hasn't worked and it will have been ruined and look 'messy' and unreadable, but.....oh well...*sigh*
My username has nothing to do with the brazilian footballer Kaka
I've never really been a fan of his in all honesty