Year	Hours
1976-01-01	2367
1977-01-01	2378
1978-01-01	2393
1979-01-01	2388
1980-01-01	2393
1981-01-01	2378
1982-01-01	2367
1983-01-01	2378
1984-01-01	2378
1985-01-01	2326
1986-01-01	2352
1987-01-01	2373
1988-01-01	2378
1989-01-01	2430
1990-01-01	2425
1991-01-01	2430
1992-01-01	2430
1993-01-01	2435
1994-01-01	2446
1995-01-01	2456
1996-01-01	2461
1997-01-01	2466
1998-01-01	2435
1999-01-01	2440
2000-01-01	2451
2001-01-01	2409
2002-01-01	2399
2003-01-01	2399
2004-01-01	2414
2005-01-01	2425
2006-01-01	2409
2007-01-01	2414
2008-01-01	2414
2009-01-01	2399
2010-01-01	2409
2011-01-01	2409