Thanks, well at lease we know there is a lot of this wallets around that he never touch and is ever going to sell, there are some crazy wallets out there and it actually fun to see the movement on the blockchain of so much money, is like standing on the traffic lane of a highway of money, something you cant do we the banking sector of course.

There is no way to estimate percentage of lost coins though. Coins haven't been moved for months or years could still be owned by someone.

You guyz are killing me.
All generated bitcoins are sitting on blockchain. None of them is lost!
People may loose their control over private keys (which is required to say "Hey, those bitcoins are mine"). That doesn't mean those bitcoins are lost forever.

How to loose bitcoins forever?
If you manage to delete some blocks from all of the full nodes; then yes we may say some of bitcoins are lost. But no, you can't do that. There're lots of offline computers which have entire blockchain. You can try to delete but you'll fail and we can recover it.

You're arguing this question: "How many bitcoins are not controlled by people?" or "How many people lost their control over their private keys? (and how many bitcoin balances are affected on those keys?)"
And the answer is "Unknown" (You can't know that). 

Also those controls can be regained by same people or others.

In conclusion; none of the bitcoins are lost. They're on the network.

that is the same thing that have the key who won 100milion dollars and didnt regist it soo it would be yours but isnt because you did paid to regist it,about wallets well some bitcoins is lost really ,some left the bitcoin and deleted all with some satoshis inside them ,besides that some people lost them on hardisks on cpu computer well some is lost  but well as i said know that have them and doesnt know keys to moove them is like be dead bitcoin

The logical conclusion is that each of these was an address setup by a miner in the first 2 years of the digital currency. The reward was paid into that address and no currency was ever added to it.

there are 14.3 million bitcoin in circulation right now so 20% is equal to 2860000BTC
you are claiming that there are 686 million dollar worth of bitcoin lost?

care to explain why you think that?

i don't know it seems a bit random, but if you look at this http://www.theguardian.com/technology/2013/nov/27/hard-drive-bitcoin-landfill-site

he only lost 7500, and it was a big lost already, but still tiny in comparison to 20% of the toal coins

i'm guessing if someone lost more than that, he would have revealed it like this guy did(but there aren't any other major news of many coins being lost), so the overall estimate of coin lost, it is very overrated i believe...

people have guesses, but there is no way to know for sure ,lot of bitcoins where lost in 2009-2010 when people formatted their drives .As the value goes up people are being more careful with their coins.

I don't think there's a way for us ever to find out, to be honest with you. But I really like to know though.