Jan ( N = None )

Feb ( N = None )

Mar ( N = None )

Apr ( N = 221 )

May ( N = 499 )

Jun ( N = 511 )

Jul ( N = 513 )

Aug ( N = 511 )

Sep ( N = 504 )

Oct ( N = 530 )

Nov ( N = 494 )

Dec ( N = 527 )