Year	Hours
1980-01-01	1859
1981-01-01	1865
1982-01-01	1877
1983-01-01	1876
1984-01-01	1865
1985-01-01	1862
1986-01-01	1870
1987-01-01	1890
1988-01-01	1893
1989-01-01	1877
1990-01-01	1867
1991-01-01	1860
1992-01-01	1863
1993-01-01	1863
1994-01-01	1857
1995-01-01	1859
1996-01-01	1873
1997-01-01	1863
1998-01-01	1880
1999-01-01	1876
2000-01-01	1861
2001-01-01	1843
2002-01-01	1831
2003-01-01	1826
2004-01-01	1826
2005-01-01	1819
2006-01-01	1815
2007-01-01	1816
2008-01-01	1803
2009-01-01	1771
2010-01-01	1775
2011-01-01	1774