PC on gold insightful earth staff of defense req 8

I need a price check on this staff please

Insightful earth staff of defense req 8 (earth)

energy +10
earth damage 11-22
halves skill recharge of spell 10%
halves casting time of spell
energy +5
armor +5

Halves casting time of spell, whats the percent on it? Need to know that before I can give you the PC.