Is it possible to get the raw data that produces that dashboard stats. In particular the proxy requests? If the chart can go back a year the stats must be on the box somewhere.
IIRC the info is here
and you can find them in per policy files called *.stat and *.tt
They are plain text, so you can just less them to get the format. TBH though I'd use SNMP to get the information out. though this does not cover per policy information it is much easer to work with.