For aftermarket sales you can check: http://dnpric.es/stats/stats-by-tld/?newgtld
They just started tracking and gathering them, so it's not much but in time we'll probably see more appear.
My advise is to look good at the left and right of the dot when regging a new gTLD. That is were the power is of those domains, many also target a niche so do your homework on that too.
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