Yes this is correct. Looking at the total bitcoin currently in circulation as many as 18,339,725 BTC. If denominated in dollars, $ 130,393,610,777.50 at current prices. If counted 51% then there are around $ 66,500,741,496.3 or around 9,353,259.75 BTC. I think it is very difficult to bring down BTC, as long as special values and consensus are still trusted.

Source: https://www.bitcoinblockhalf.com/