How many BTC have been paid in fees, in total? Is there a graph or some data points for the total BTC paid in fees?

I'm interested in total BTC as % of the issued BTC at various points in time as well.
https://www.blockchain.com/en/charts it's for you. In addition to being graphs of any kind, if you scroll to the bottom of the page you will find the Total Transaction Fees chart.

The total as of 2019-08-15 was 66967,60 BTC or 0.37% of the total coins in circulation on that day.