Year	Percent
1960-01-01	42.00390000000000
1961-01-01	40.85060000000000
1962-01-01	36.29630000000000
1963-01-01	84.77510000000000
1964-01-01	107.55300000000000
1965-01-01	101.61100000000000
1966-01-01	103.87299999999999
1967-01-01	102.36000000000000
1968-01-01	101.49900000000000
1969-01-01	103.90500000000000
1970-01-01	113.47900000000000
1971-01-01	121.31900000000000
1972-01-01	112.88900000000000
1973-01-01	92.93220000000000
1974-01-01	86.15750000000000
1975-01-01	87.56210000000000
1976-01-01	68.93030000000000
1977-01-01	60.22120000000000
1978-01-01	69.91870000000000
1979-01-01	56.11630000000000
1980-01-01	31.05480000000000
1981-01-01	25.58280000000000
1982-01-01	25.71650000000000
1983-01-01	22.93450000000000
1984-01-01	19.17120000000000
1985-01-01	15.83830000000000
1986-01-01	14.08800000000000
1987-01-01	15.65280000000000
1988-01-01	14.83390000000000
1989-01-01	11.34570000000000
1990-01-01	10.36090000000000
1991-01-01	9.80436000000000
1992-01-01	11.20540000000000
1993-01-01	18.88170000000000
1994-01-01	25.42190000000000
1995-01-01	36.17710000000000
1996-01-01	56.39730000000000
1997-01-01	62.75190000000000
1998-01-01	61.25400000000000
1999-01-01	66.92340000000000
2000-01-01	68.49400000000000
2001-01-01	63.00730000000000
2002-01-01	56.24710000000000
2003-01-01	50.61740000000000
2004-01-01	47.66550000000000
2005-01-01	50.52190000000000
2006-01-01	57.76030000000000
2007-01-01	60.09700000000000
2008-01-01	62.27160000000000
