Yep, it's still above 100% PPS, due to luck, since the pool started.

Anyone who joined since block 330642 started, has of course not had that luck.

The number at the bottom of the blocks page shows the average % of a block for all blocks found, so 55.09% up to when block 330642 was found, means the pool has found 1.8 times the number of expected blocks and we pay out 99.1% of every block (+ txn fees) the pool finds, to the miners.
https://www.kano.is/index.php?k=pblocks

Of course, when the next block is found, the 55.09% number will go up, and the 1.8 times number will go down.

The average expected payout per block on any PPLNS pool over a long period of time, is of course the payout % of a block the pool pays - which is 99.1% here.
But of course, since we include txn fees in the payout, that is a bit higher than the 99.1% expected.