Jan ( N = 310 )

Feb ( N = 280 )

Mar ( N = 309 )

Apr ( N = 300 )

May ( N = 310 )

Jun ( N = 300 )

Jul ( N = 310 )

Aug ( N = 310 )

Sep ( N = 300 )

Oct ( N = 310 )

Nov ( N = 300 )

Dec ( N = 310 )