If the average congregate gives $50 per month that is $125,000,000 per month and $1,500,000,000 per year.
kwr: I think there is confusion over this word - is it "congregation" or "congregant" (individual members)?
If you mean individuals, I think $50 per month is way over the top for most dubs. I remember one time my mom instructing my dad to put some $$ in the contribution box. My dad figured out later he may have put in a $20 bill instead of $1. We were pretty poor - such that dad called the brother in charge of accounts to get his $$ back. Sure enough, among the $1 bills, was a twenty. Dad asked for $19 change. Embarrassing. I don't think dad ever put money in the box again.