You can see how often new releases come out by going to the download archives webpage and looking at the dates that Ignition versions have been released.
I see:
Ignition 7.6.6 Release Date: Apr 1, 2014
Ignition 7.6.4 Release Date: Nov 22, 2013
Ignition 7.6.3 Release Date: Sep 5, 2013
Ignition 7.6.2 Release Date: Jul 2, 2013
Ignition 7.6.1 Release Date: May 28, 2013
etc…