Any guesstimates at the number of bitcoins that have been lost for good?

So many people seem to have had thousands of coins from ages ago that they've lost and will forever be lost.

As we all know the supply isn't increasing so all these lost coins are deflationary.

But is there any idea on how many of the 19,958,312 coins will be forever out of circulation?

I received something like 0.05 of a coin for opening a wallet back in 2014 that I've lost.