Monthly Hours
1987-01-01 29720000
1987-02-01 34300000
1987-03-01 33560000
1987-04-01 31280000
1987-05-01 31280000
1987-06-01 31180000
1987-07-01 11510000
1987-08-01 31500000
1987-09-01 34130000
1987-10-01 33810000
1987-11-01 34590000
1987-12-01 29130000
1988-01-01 29820000
1988-02-01 33870000
1988-03-01 33080000
1988-04-01 31680000
1988-05-01 31780000
1988-06-01 31420000
1988-07-01 13710000
1988-08-01 31790000
1988-09-01 32960000
1988-10-01 33910000
1988-11-01 35590000
1988-12-01 28540000
1989-01-01 30450000
1989-02-01 34990000
1989-03-01 33340000
1989-04-01 30570000
1989-05-01 31800000
1989-06-01 32540000
1989-07-01 12310000
1989-08-01 32980000
1989-09-01 34180000
1989-10-01 32680000
1989-11-01 35410000
1989-12-01 29520000
1990-01-01 30090000
1990-02-01 33930000
1990-03-01 33190000
1990-04-01 30320000
1990-05-01 30300000
1990-06-01 31610000
1990-07-01 11570000
1990-08-01 32810000
1990-09-01 33210000
1990-10-01 32430000
1990-11-01 33280000
1990-12-01 27530000
1991-01-01 29420000
1991-02-01 31900000
1991-03-01 31260000
1991-04-01 29480000
1991-05-01 28420000
1991-06-01 28860000
1991-07-01 10340000
1991-08-01 30010000
1991-09-01 29950000
1991-10-01 30450000
1991-11-01 30920000
1991-12-01 25120000
1992-01-01 27210000
1992-02-01 29170000
1992-03-01 29160000
1992-04-01 27110000
1992-05-01 26220000
1992-06-01 27210000
1992-07-01 8790000
1992-08-01 26850000
1992-09-01 29070000
1992-10-01 28460000
1992-11-01 29030000
1992-12-01 23490000
1993-01-01 24320000
1993-02-01 26390000
1993-03-01 26930000
1993-04-01 24020000
1993-05-01 25170000
1993-06-01 24960000
1993-07-01 10820000
1993-08-01 24100000
1993-09-01 27490000
1993-10-01 27010000
1993-11-01 27140000
1993-12-01 22670000
1994-01-01 23900000
1994-02-01 26400000
1994-03-01 24830000
1994-04-01 25890000
1994-05-01 23780000
1994-06-01 25870000
1994-07-01 11810000
1994-08-01 24320000
1994-09-01 27080000
1994-10-01 28710000
1994-11-01 28450000
1994-12-01 24340000
1995-01-01 26660000
1995-02-01 27990000
1995-03-01 27440000
1995-04-01 25850000
1995-05-01 25270000
1995-06-01 26150000
1995-07-01 13270000
1995-08-01 25170000
1995-09-01 28980000
1995-10-01 30550000
1995-11-01 30070000
1995-12-01 25000000
1996-01-01 27370000
1996-02-01 29110000
1996-03-01 28520000
1996-04-01 26630000
1996-05-01 25500000
1996-06-01 27280000
1996-07-01 13720000
1996-08-01 23740000
1996-09-01 28090000
1996-10-01 29630000
1996-11-01 29550000
1996-12-01 24870000
1997-01-01 22500000
1997-02-01 28290000
1997-03-01 27820000
1997-04-01 28110000
1997-05-01 23000000
1997-06-01 28360000
1997-07-01 14980000
1997-08-01 23020000
1997-09-01 28640000
1997-10-01 29820000
1997-11-01 29230000
1997-12-01 25220000
1998-01-01 21590000
1998-02-01 28110000
1998-03-01 28790000
1998-04-01 26260000
1998-05-01 25550000
1998-06-01 27470000
1998-07-01 15890000
1998-08-01 22590000
1998-09-01 28930000
1998-10-01 29570000
1998-11-01 29000000
1998-12-01 21670000
1999-01-01 26500000
1999-02-01 28130000
1999-03-01 26340000
1999-04-01 27410000
1999-05-01 25690000
1999-06-01 26640000
1999-07-01 14100000
1999-08-01 24320000
1999-09-01 28050000
1999-10-01 28840000
1999-11-01 28560000
1999-12-01 23700000
2000-01-01 25150000
2000-02-01 27820000
2000-03-01 27470000
2000-04-01 25680000
2000-05-01 27760000
2000-06-01 24360000
2000-07-01 14140000
2000-08-01 23000000
2000-09-01 28080000
2000-10-01 29240000
2000-11-01 28590000
2000-12-01 24170000
2001-01-01 26080000
2001-02-01 28410000
2001-03-01 26900000
2001-04-01 24860000
2001-05-01 24620000
2001-06-01 25140000
2001-07-01 13200000
2001-08-01 22180000
2001-09-01 26390000
2001-10-01 27320000
2001-11-01 28400000
2001-12-01 21740000
2002-01-01 22130000
2002-02-01 26990000
2002-03-01 24880000
2002-04-01 25120000
2002-05-01 22100000
2002-06-01 24810000
2002-07-01 12630000
2002-08-01 20780000
2002-09-01 25600000
2002-10-01 25700000
2002-11-01 26430000
2002-12-01 21970000
2003-01-01 19380000
2003-02-01 25350000
2003-03-01 25720000
2003-04-01 22740000
2003-05-01 23700000
2003-06-01 23100000
2003-07-01 12250000
2003-08-01 19000000
2003-09-01 25150000
2003-10-01 25530000
2003-11-01 24670000
2003-12-01 21620000
2004-01-01 17900000
2004-02-01 24770000
2004-03-01 24910000
2004-04-01 22780000
2004-05-01 22890000
2004-06-01 23410000
2004-07-01 13820000
2004-08-01 17650000
2004-09-01 25070000
2004-10-01 25080000
2004-11-01 25140000
2004-12-01 21120000
2005-01-01 21950000
2005-02-01 24050000
2005-03-01 22940000
2005-04-01 24520000
2005-05-01 22400000
2005-06-01 23190000
2005-07-01 12200000
2005-08-01 17730000
2005-09-01 24210000
2005-10-01 23840000
2005-11-01 24420000
2005-12-01 21150000
2006-01-01 21230000
2006-02-01 22830000
2006-03-01 24460000
2006-04-01 21460000
2006-05-01 21460000
2006-06-01 22390000
2006-07-01 13080000
2006-08-01 18640000
2006-09-01 24260000
2006-10-01 24910000
2006-11-01 23970000
2006-12-01 20680000
2007-01-01 22870000
2007-02-01 23240000
2007-03-01 23900000
2007-04-01 22170000
2007-05-01 21460000
2007-06-01 22600000
2007-07-01 12800000
2007-08-01 18450000
2007-09-01 24010000
2007-10-01 24720000
2007-11-01 24300000
2007-12-01 20300000
2008-01-01 20790000
2008-02-01 24140000
2008-03-01 21770000
2008-04-01 24920000
2008-05-01 22280000
2008-06-01 22480000
2008-07-01 13790000
2008-08-01 17160000
2008-09-01 23010000
2008-10-01 25170000