Start of the period	End of the period	Due date
January	2011-01-01	2011-01-31	2011-02-28
February	2011-02-01	2011-02-28	2011-03-31
March	2011-03-01	2011-03-31	2011-05-02
April	2011-04-01	2011-04-30	2011-05-31
May	2011-05-01	2011-05-31	2011-06-30
June	2011-06-01	2011-06-30	2011-08-01
July	2011-07-01	2011-07-31	2011-08-31
August	2011-08-01	2011-08-31	2011-09-30
September	2011-09-01	2011-09-30	2011-10-31
October	2011-10-01	2011-10-31	2011-11-30
November	2011-11-01	2011-11-30	2012-01-04
December	2011-12-01	2011-12-31	2012-01-31