Hmmm you are right, the site is down and https://deeponion.org/stats.html is also dead (i believe it the same target just not sure).
Anyone know anything about this?
I actually came by to ask nearly the same thing. More importantly to me, is when using a custom change address, how to verify the amount of Onion we have been airdropped so that we don't accidentally disqualify ourselves? I'm assuming that I have just become lazy and not given it enough thought and it can be accomplished using the block explorer, any hints on accomplishing the extra bit of caution I want?
Just check into your unspent transactions (coin control inputs button in the send tab) and make sure all your coin is into the airdrop. When you move coins set your custom on the airdrop address, that way you'll be safe.
Unless you move coins outside of your wallet (like on nova), then this is a different story and if you go below 90% of the airdrop received coins you could be in trouble.