"WARNING: Forgotten passwords are UNRECOVERABLE and will results in LOSS of ALL of your bitcoins!"
I hate when my banker says this to me about online banking.
Then use Coinbase, which says "you'll have to trust us with your coin, and hope we don't get hacked".
Honestly, I prefer it to "WARNING: Your password must be 6-8 characters and contain no numbers or symbols"
Thats the number of accounts on a website. Anyone can create as many accounts as they want and they don't limit that chart to accounts with bitcoin. It's a pointless metric that is easily faked. Given the number of wallets with bitcoin in them worth >$50 isn't really growing I'd say its pretty likely a lot of those are fake/unused accounts.