Year	Percent
1970-01-01	13.692329260
1971-01-01	13.529605320
1972-01-01	16.484860920
1973-01-01	18.454586970
1974-01-01	24.137867200
1975-01-01	25.325298800
1976-01-01	29.813594000
1977-01-01	29.130908080
1978-01-01	25.409684260
1979-01-01	17.821876850
1980-01-01	20.608466160
1981-01-01	23.970734530
1982-01-01	20.698297640
1983-01-01	11.683460080
1984-01-01	8.603938819
1985-01-01	10.305970240
1986-01-01	15.488500710
1987-01-01	18.466955060
1988-01-01	12.020255120
1989-01-01	15.939373330
1990-01-01	16.935833610
1991-01-01	16.912849920
1992-01-01	17.884453720
1993-01-01	19.863453330
1994-01-01	37.639001130
1995-01-01	42.691045030
1996-01-01	30.429074120
1997-01-01	23.993445460
1998-01-01	17.613992170
1999-01-01	69.327386970
2000-01-01	63.227569530
2001-01-01	62.318089790
2002-01-01	75.064611670
2003-01-01	68.747035230
2004-01-01	82.932717580
2005-01-01	80.781369210
2006-01-01	66.203871490
2007-01-01	71.763903250
2008-01-01	72.409943980
2009-01-01	72.580192660
2010-01-01	67.068611210