Year	Hours
1970-01-01	2033
1971-01-01	2024
1972-01-01	2040
1973-01-01	2072
1974-01-01	2023
1975-01-01	1989
1976-01-01	2023
1977-01-01	2063
1978-01-01	2095
1979-01-01	2121
1980-01-01	2137
1981-01-01	2127
1982-01-01	2122
1983-01-01	2118
1984-01-01	2131
1985-01-01	2114
1986-01-01	2112
1987-01-01	2117
1988-01-01	2119
1989-01-01	2093
1990-01-01	2065
1991-01-01	2019
1992-01-01	1976
1993-01-01	1921
1994-01-01	1912
1995-01-01	1914
1996-01-01	1915
1997-01-01	1886
1998-01-01	1864
1999-01-01	1846
2000-01-01	1860
2001-01-01	1842
2002-01-01	1829
2003-01-01	1833
2004-01-01	1840
2005-01-01	1829
2006-01-01	1839
2007-01-01	1829
2008-01-01	1811
2009-01-01	1762
2010-01-01	1782
2011-01-01	1727