Nowadays, 7 big blinds per 100 hands is considered a very solid winrate at midstakes games (2/4 through 5/10). This is actually described as 3.5bb/100 which is read as 3.5 "big bets" per 100 hands, which is the traditional system used for limit hold'em, where a big bet is two big blinds. I remember way back in 2003/2004 when PartyPoker was the most popular site and people were posting graphs of 10bb/100 (big bets) winrates at stakes as high as 10/20 over hundreds of thousands of hands. The fact that having a winrate like that is impossible today even at stakes as low as 1/2 shows you how much tougher the games have become.