im interested to know why you think that?
tevez since he joined city: 51 goals in 88 apps = 0.625
aguero: 25/41 = 0.609
so he has a better goals to game ratio than aguero, who you say you're a fan of.
tevez also starred at the birth of the city era when he was the only big star whilst aguero's career consisted of playing with many world class players like silva and yaya.