It's definitely easier to check them later in the day, than earlier in the morning, at least for me. However, 50+ in an hour would be nearly impossible, so kudos to you for getting through them all (as I can personally attest you do)!
For me it also depends on how active I am with commenting and sharing posts that people appreciate and therefor comment on. On an average per hour is hard say, but per day... Probably around 5-10. I check my notifications asap as well, so that is also why it's pretty difficult to say how many I get in an hour too or per day.