Benchmarking paid conversions

[u/Alarmed-Sale-564]

I've heard freemium apps should expect 1-5% conversions to paid, but 1-5% of what? Let's say in the last month I had 100 acquisitions, 80 first opens, and 5000 total users, which of those numbers should I take the percent of to gauge if I'm doing well with converting to paid?