One question to suprnova.cc and mining btcz. As long as I am watching BtcZ suprnova constantly held above 50% of the global hashing power. But if you look at their stats they are over the whole time just finding around 20% of all blocks:

First Value are the global blocks, second one suprnovas findings

Last 24h   1,440   257   
Last 7d   10,080   1,940
Last 4w   40,320   8,261

You can have a look here: https://btcz.suprnova.cc/index.php?page=statistics&action=blocks

Can someone explain this to me please?