Year	Percent
1961-01-01	0.8483980000000000
1962-01-01	0.7734810000000001
1963-01-01	2.7662800000000000
1964-01-01	4.8650500000000000
1965-01-01	5.2271300000000010
1966-01-01	5.6301100000000000
1967-01-01	6.0377400000000000
1968-01-01	6.3673699999999990
1969-01-01	6.8395500000000000
1970-01-01	4.3761100000000000
1971-01-01	4.8949900000000000
1972-01-01	5.0628300000000000
1973-01-01	5.2823199999999995
1974-01-01	5.2339900000000000
1975-01-01	5.0592400000000000
1976-01-01	4.5274700000000000
1977-01-01	4.2289400000000010
1978-01-01	4.9926900000000005
1979-01-01	4.2608900000000000
1980-01-01	2.4100700000000000
1981-01-01	2.1540600000000000
1982-01-01	2.3275700000000000
1983-01-01	2.1227700000000000
1984-01-01	2.2093900000000000
1985-01-01	1.9846200000000000
1986-01-01	1.7980599999999998
1987-01-01	1.9874700000000000
1988-01-01	1.9821799999999998
1989-01-01	1.6139400000000000
1990-01-01	1.4926900000000000
1991-01-01	1.5921700000000000
1992-01-01	1.7460000000000000
1993-01-01	2.6002800000000000
1994-01-01	4.0976099999999995
1995-01-01	5.9395600000000000
1996-01-01	9.1683300000000010
1997-01-01	12.6128000000000000
1998-01-01	15.2438000000000000
1999-01-01	17.5938000000000000
2000-01-01	18.1104000000000000
2001-01-01	17.6245000000000000
2002-01-01	17.7978000000000000
2003-01-01	17.5358000000000000
2004-01-01	15.8152000000000000
2005-01-01	16.4436000000000000
2006-01-01	17.9315000000000000
2007-01-01	17.1681000000000000
2008-01-01	17.0585000000000000