I'm sure it was since Pedro's debut? Messi's debut was in 2004 and Eto'o scored a lot more goals until he left in 2009 than Pedro did between 2008 and today. Since Pedro's debut he played significantly more minutes than all the other successful attackers. Neymar is there for only 2 seasons, Suarez for 1. Villa only had one and a half seasons before he broke his leg, Ibra had one season, Henry and Eto'o also only one.
Alexis Sanchez is usually considered a failure at Barca, but in his 3 seasons at Barca he still scored more goals than Pedro while playing less minutes.