If you want to know how many registrations made for each of the new gTLD then go to www.ntldstats.com and click the new gTLD and you’ll find the list of all new gTLDs which have made upto the general availability phase as well as some who’re under sunrise and landrush period.
Off all the new gTLDs .Guru is leading with more than fifty thousand registraions, followed by .berlin, .email, .link, etc. With continuous flow of new gTLDs everyday, it seems that the new gTLDs which have not yet arrived and are scheduled to arrive may not get the same attraction which the earlier new gTLDs have got such as .Guru, .Email, .Link, etc.
The most active community who’re well aware of all new gTLDs are domaining community and it’s a type of community which buys/registers domains based on risk/return ratio and not just to build websites. Since, most of the domainers don’t invest in new gTLDs and some who may’ve already invested in earlier released new gTLDs may reduce their investment amount or not at all invest in the upcoming new gTLDs. Such a scenario will further reduce the new registrations of new gTLDs.
If registries want to sustain upcoming new gTLDs then the place to go is to massively advertise and attract the general people who may buy a new gTLD for their business, passion or just to hold one. The system to release new gTLDs in such a rush manner is somewhat incomprehensible to me as it’s clearly evident from registrations that new gTLDs are losing and especially those who’re yet to arrive may find it difficult to have buyers.