Year	Percent
1960-01-01	25.960000000000000
1961-01-01	22.716300000000000
1962-01-01	18.786600000000000
1963-01-01	20.105400000000000
1964-01-01	19.033200000000000
1965-01-01	18.237800000000000
1966-01-01	19.464100000000000
1967-01-01	14.541800000000000
1968-01-01	9.431569999999999
1969-01-01	8.488260000000000
1970-01-01	9.017489999999999
1971-01-01	7.472840000000000
1972-01-01	6.136120000000000
1973-01-01	5.914280000000001
1974-01-01	4.526580000000000
1975-01-01	3.751800000000000
1976-01-01	3.945650000000000
1977-01-01	4.419430000000000
1978-01-01	4.542410000000000
1979-01-01	5.161180000000000
1980-01-01	5.367390000000000
1981-01-01	4.829130000000000
1982-01-01	5.705010000000000
1983-01-01	7.015530000000000
1984-01-01	8.155250000000000
1985-01-01	7.799780000000000
1986-01-01	7.114190000000000
1987-01-01	7.074300000000000
1988-01-01	5.618330000000000
1989-01-01	6.670850000000000
1990-01-01	6.954839999999999
1991-01-01	7.509150000000000
1992-01-01	8.502730000000000
1993-01-01	9.918590000000000
1994-01-01	8.852839999999999
1995-01-01	9.878200000000000
1996-01-01	9.508910000000000
1997-01-01	9.368150000000000
1998-01-01	9.193280000000000
1999-01-01	8.959150000000000
2000-01-01	7.945620000000000
2001-01-01	7.638460000000000
2002-01-01	6.955640000000000
2003-01-01	8.783450000000000
2004-01-01	9.628200000000000
2005-01-01	11.694600000000000
2006-01-01	13.735200000000000
2007-01-01	13.559800000000000
2008-01-01	14.827600000000000
2009-01-01	17.460900000000000
2010-01-01	19.650300000000000