delete or clear statistic/graft data

hello.. how do i delete this graft data because all this are testing data.. so now i plan to move to production.. FYI i already delete all testing ticket data but the figure on this graft still remain..please help..in what table should i clear this data?

osTicket Version     v1.9.12 (19292ad) — Up to date
Web Server Software     Apache/2.4.10 (Win32) OpenSSL/1.0.1i PHP/5.5.19
MySQL Version     5.6.21
PHP Version     5.5.19

Thank You