We have so many PHs! I hope this evens out statistically and we all make out. We're soooooooo due.
Actually with 15PH we are actually due less than one block a day. 11BTC at the current difficulty level.
Expected at current difficulty and total pool hash (15.2PH)
0.4586 BTC/hour (0.036688 blocks)
11.01 BTC/day (0.88 blocks)
77.04 BTC/week (6.16 blocks)
330.2 BTC/month (26.4 blocks)
Of course difficulty levels change during the month as does the hashrate of the pool, so these numbers are just a point in time snapshot and cannot be used to predict past or future returns.