Year	Percent
1960-01-01	1.28994585412464
1961-01-01	1.13177470775770
1962-01-01	1.28029504741834
1963-01-01	1.41172820353708
1964-01-01	1.13172920065253
1965-01-01	1.40276516298315
1966-01-01	1.43679599499374
1967-01-01	1.90618019359643
1968-01-01	2.33626745030772
1969-01-01	1.98362330686504
1970-01-01	2.22606615548188
1971-01-01	2.40238822720322
1972-01-01	2.44646874513355
1973-01-01	2.35830770927289
1974-01-01	2.55667003995939
1975-01-01	3.70276350614808
1976-01-01	4.01132713166042
1977-01-01	4.56233360578960
1978-01-01	4.54029334682443
1979-01-01	5.15742059784912
1980-01-01	5.51006474129179
1981-01-01	6.50187639472431
1982-01-01	7.14104390471416
1983-01-01	7.31736597643550
1984-01-01	8.52958021951969
1985-01-01	9.03650617571854
1986-01-01	9.16874772950954
1987-01-01	9.27894902433537
1988-01-01	8.81610358606686
1989-01-01	8.28713737090285
1990-01-01	7.86837245056468
1991-01-01	8.30917762986802
1992-01-01	9.05119968169531
1993-01-01	10.21933340684920
1994-01-01	10.65279183316410
1995-01-01	10.04301133512780
1996-01-01	10.55897672872710
1997-01-01	10.71514205265130
1998-01-01	10.28640790272750
1999-01-01	9.98469884338232
2000-01-01	8.52741053378199
2001-01-01	7.74169505198117
2002-01-01	7.87923189959734
2003-01-01	8.12500000000000
2004-01-01	8.47500000000000
2005-01-01	8.50000000000000
2006-01-01	8.45000000000000
2007-01-01	7.65000000000000
2008-01-01	7.07500000000000
2009-01-01	8.72500000000000
2010-01-01	8.85000000000000
2011-01-01	8.80000000000000
2012-01-01	9.40000000000000
2013-01-01	9.92500000000000
2014-01-01	10.32500000000000
2015-01-01	10.37500000000000
2016-01-01	10.05000000000000
2017-01-01	9.40000000000000