Statistics were reset

I took a backup of Statistics and threw it back to the server was reset , why is this happening ?

thx

stats.db back up the file, have installed again stats are reset

this source could be a problem?
[statistics]
statsstring = "^2Kills: <KILLS> ^1Deaths: <DEATHS> ^3K/D: <KPD> ^2time: <ONLINETIME> min ^3K/M: <KPM> ^2HS: <HEADSHOTS> ^7TKs: <TEAMKILLS>"
whisperstats = 0
savestats = "0"