Last October a website called BTCBurns.cf identified 397 burn addresses containing 2,657.8686 BTC lost forever. It has gone offline. Since it stopped keeping track 26.04 additional bitcoins have been sent to these addresses.
The total number of unspendable bitcoins is now 2,771.4086.
http://bitcoinwhoswho.com/blog/2016/12/21/btc-burn-addresses/It would be cool to be able to keep real track of the amount of burned addresses, but only those addresses that are publicly know to be as burning address can provide us efficient data in keeping track of real lost forever bitcoins.
if we take into consideration that the address of satoshi nakamoto contain up to 1 million bitcoins, we may think that the amount of burned BTC is over 1 million now, since its safe to assume satoshis keys are lost for life.