Year	Percent
1960-01-01	3.7910000000000004
1961-01-01	4.2949400000000000
1962-01-01	4.9992600000000000
1963-01-01	5.0262800000000000
1964-01-01	5.4562700000000000
1965-01-01	5.6027500000000000
1966-01-01	5.7634099999999995
1967-01-01	5.9841900000000000
1968-01-01	6.5697500000000000
1969-01-01	7.1723100000000000
1970-01-01	6.6626100000000010
1971-01-01	6.8877800000000000
1972-01-01	7.4042200000000000
1973-01-01	6.9653199999999990
1974-01-01	5.6332400000000000
1975-01-01	5.6698200000000000
1976-01-01	7.1290300000000000
1977-01-01	8.2036800000000000
1978-01-01	8.5729700000000000
1979-01-01	8.5970600000000000
1980-01-01	9.5808400000000000
1981-01-01	10.9276000000000000
1982-01-01	12.1533000000000000
1983-01-01	11.8095000000000000
1984-01-01	10.5390000000000010
1985-01-01	8.4413100000000010
1986-01-01	4.7545500000000000
1987-01-01	2.7085800000000000
1988-01-01	2.8565800000000000
1989-01-01	2.9007099999999997
1990-01-01	2.9393100000000000
1991-01-01	3.4155000000000000
1992-01-01	4.2472000000000000
1993-01-01	5.0751400000000000
1994-01-01	6.0434199999999990
1995-01-01	6.9669100000000000
1996-01-01	6.2052400000000000
1997-01-01	5.1266600000000000
1998-01-01	5.0032100000000000
1999-01-01	4.5633700000000000
2000-01-01	4.2178300000000000
2001-01-01	4.1768300000000010
2002-01-01	4.2176500000000000
2003-01-01	4.1810199999999990
2004-01-01	4.0210099999999995
2005-01-01	4.1353800000000005
2006-01-01	4.4584400000000000
2007-01-01	4.6413300000000000