Google Analytics provides a summary of the audience for the iCAP Portal.  This data is available to iCAP portal administrators, and this metric is based on the subcategory called "iCAP Portal (Exclude MSTE Traffic)."  This metric is for the time ranges of July 1 to June 30 for each fiscal year, since the Portal went live in spring 2013.  It is the # of "Users" in the Audience Overview section of Google Analytics.