60-70% is pretty good like others already said above
i got anywhere between 30-70% when i did ig marketing seriously, not with one, not with two acc, but with thousands of accs lol, so i guess i was averaging around 50%
once there was this glitch in ig where you could follow the max limit with a click of a button in a matter of a minute or two using a bot, at that time i used 50 fresh accs daily to max out the following limit and after 1-2 days, the vast majority of the accs have around 3k followers each besides the 7.5k following, it was very rare to get less than 2k followers, but it was also pretty rare to go above 5k, although it always happened with one or two accs in the 50 batches, you do the maths
i used the same ancient tactic which i used on twitter before, i picked the 50 most followed accs and i followed their most recent 7.5k followers, because these top followed accs easily got this many followers in a day and i wanted to make sure, that i follow active people, although they were pretty random, but i wasn't targeting any specific niche
following 350k people every day for a few months, i think i can say it was a big enough, representative sample, but i still wasn't able to draw any conclusions - i wasn't really trying though - with the very same or almost the same settings, i got different results
all the accs i used were sexy girl accs, so it can be the different pictures, the different "feeder" accs i used to get their followers, the mixture of this two or something entirely different, hard to tell
i'm not sure if discussing these numbers would make any sense though without knowing the whole story behind the numbers, what you obviously can't really expect from anybody