why lookup is not working and returning #N/A ? thanks

doing :
=LOOKUP(PRET,G4:G13,F4:F13) on the range below,
the result should be 990, it works only for the first 8 items in the lookup
array

PRET

990 SIM1
990 SIM2
990 SIM3
990 SIM4
990 SIM5
990 SIM6
990 TLOW
990 THIGH
990 PRET
990 POST