While 2014 visitation for Rocky Mountain National Park totaled 3,443,501 visitors, the park also keeps monthly statistics. Each of these reports can be found on the IRMA portal. They break down even further to include monthly campground and visitor center use information since 1996. If you're a number cruncher go to the IRMA Portal Park Reports site to see all the reports from 1904 to the present day.
A complete working species list of all living things in the park is also available to peruse on the IRMA Portal NP Species page.