Your website is full of information. It's like a wonder where one can see a lot of details about Bitcoin and the numbers that one can ever find. It's  with everything and even the conversion from different currencies.
Just a noob question. We knew that 21 million is the maximum supply of Bitcoin and I've seen that there's 20,999,999.97 on your website's supply. Is there an explanation technically why it's not whole 21 million?