Mobile analytics firm Distimo has published some research into the number of downloads required to get into Apple’s App Store Top 25 category charts in the US with an iPhone app. To break the Top 25 of all iPhone apps, you need 38.4k daily downloads for a free app, but for the Music category, that number is 3.9k. And for a paid music app? If Distimo is to be believed, it only requires 80 sales. Eight Zero! Which provides useful context for anyone boasting about the Top 25 ranking for their music app. That said, we suspect the numbers ramp up a lot by the time you reach the top 10 or top five even in the Music category.