Our last annual tally of ~400 known "burn addresses", that is bitcoin addresses with almost assuredly no known private key, totaled 2,759.42507135 BTC as of Dec 2017.
If those lists are accurate and the tally is as you say BTC 2759.42507135 then they will be worth at the current rate of exchange to the US Dollar. (Which is no small change in the big picture)