As of June 2, 2015, the number of marks submitted is 37,151. This means that 37,151 second level domain names have this rights protection mechanism that allows trademark holders to the 2 benefits listed above.
Doing some mathematical calculations with the previous TMCH statistics, cf. TMCH stats April 21st 2015, the current rate of new marks added to the Trademark Clearinghouse averages out to about 25 marks submitted each day or about 180 marks submitted weekly. That's the estimate of how many names are added to the TMCH each day.
ICANN (Internet Corporation for Assigned Names and Numbers) launches something called the Trademark Clearinghouse "as a way for trademark owners to protect their intellectual property... the clearinghouse will allow trademark owners to register their marks before a new TLD is launched and protect their trademarks if other companies try to register a website using their trademarks after a TLD is operating. The new service isn’t free, with the cost of registering a trademark ranging between $95 and $150 a year...."
Andrew Alleman explained that records in the Trademark Clearinghouse benefit trademark holders in two ways: