Summary Stats for a KPI Report

I am trying to pull uptime statistics for Network report we give to senior leadership. I need Last Months %, in a graphical form. I can get an all-nodes report but would like to summarize that by site/group, with individual %'s per group.

Any easy ideas/ways to do this in SolarWinds? We just converted from other monitoring tools and i have not yet figured this one out here.