Jan ( N = 160 )

Feb ( N = 210 )

Mar ( N = 260 )

Apr ( N = 300 )

May ( N = 310 )

Jun ( N = 300 )

Jul ( N = 310 )

Aug ( N = 310 )

Sep ( N = 300 )

Oct ( N = 310 )

Nov ( N = 120 )

Dec ( N = 230 )