Benchmarks for % of email database opt-outs

Hello Team,

Not sure if this exists but I am looking for a benchmark for what percent of your entire email database should be opt-out. I know there are opt-rates per campaign usually around .1% - .5% and some even say say below 2%. However, what is the number for your entire email database. I am currently running at 5% of my entire email database. Not sure if that is good or bad.

Appreciate any help.