https://theconversation.com/3-questions-about-the-fisa-court-answered-91208

In 2016, the FISA court reviewed 1,485 requests for surveillance. While higher than the number of requests reviewed in 2014 (1,379) and 2015 (1,457), the number of requests has remained at 1,200 or higher since 2001.

It is rare for these requests to be denied. Of the requests made in 2016, only 34 were rejected. In most years, no requests were denied.

Since the proceedings of the court are secret, it is unclear why these denials occurred or why so few cases were denied.

It is also unclear how the current controversy over the Nunes memo will affect FISA operations in the future, if at all.