00]
Categories (5, datetime64[ns, US/Eastern]): [2011-01-01 09:00:00-05:00, 2011-01-01 10:00:00-05:00,
                                             2011-01-01 11:00:00-05:00, 2011-01-01 12:00:00-05:00,
                                             2011-01-01 13:00:00-05:00]a