2.2586% achieved towards the next +0.00000024 BTC bonus!
That one.
OK, you do not need to invest anything. It is a ratio of how much you gamble on Hi-Lo, Jackpots and buy lottery tickets vs. how much you win in Free-Rolls. As it is a ratio the amount is different for everyone based on their unique history of betting and claiming Free-Rolls.
I deposited some money and my earnings went up. Therefore I thought the amount you deposit has influence on your earnings (and the captcha's).