year	hrs
1876	5
1877	3
1878	4
1879	9
1880	6
1881	7
1882	7
1883	10
1884	27
1885	11
1886	11
1887	17
1888	14
1889	20
1890	14
1891	16
1892	13
1893	19
1894	18
1895	17
1896	13
1897	11
1898	15
1899	25
1900	12
1901	16
1902	16
1903	13
1904	10
1905	9
1906	12
1907	10
1908	12
1909	9
1910	10
1911	21
1912	14
1913	19
1914	19
1915	24
1916	12
1917	12
1918	11
1919	29
1920	54
1921	59
1922	42
1923	41
1924	46
1925	39
1926	47
1927	60
1928	54
1929	46
1930	56
1931	46
1932	58
1933	48
1934	49
1935	36
1936	49
1937	46
1938	58
1939	35
1940	43
1941	37
1942	36
1943	34
1944	33
1945	28
1946	44
1947	51
1948	40
1949	54
1950	47
1951	42
1952	37
1953	47
1954	49
1955	51
1956	52
1957	44
1958	47
1959	46
1960	41
1961	61
1962	49
1963	45
1964	49
1965	52
1966	49
1967	44
1968	44
1969	49
1970	45
1971	48
1972	40
1973	44
1974	36
1975	38
1976	38
1977	52
1978	46
1979	48
1980	48
1981	31
1982	39
1983	40
1984	43
1985	40
1986	40
1987	49
1988	42
1989	47
1990	51
1991	44
1992	43
1993	46
1994	43
1995	50
1996	52
1997	58
1998	70
1999	65
2000	50
2001	73
2002	57
2003	47