Year	Percent
1960-01-01	3.27424913835592
1961-01-01	6.69845053635204
1962-01-01	1.40750670241320
1963-01-01	1.76250275391076
1964-01-01	2.01342281879184
1965-01-01	2.63157894736850
1966-01-01	1.90239867659224
1967-01-01	3.02353896103861
1968-01-01	5.92869805002992
1969-01-01	6.30345853477093
1970-01-01	14.72800419625670
1971-01-01	5.33617929585860
1972-01-01	5.42770299630755
1973-01-01	17.68259198248370
1974-01-01	27.15818945502170
1975-01-01	17.37614678858000
1976-01-01	9.79365327534655
1977-01-01	11.19100163703580
1978-01-01	34.89980152405080
1979-01-01	29.07925961097860
1980-01-01	27.30815898823070
1981-01-01	12.73971811450910
1982-01-01	6.54540796720071
1983-01-01	11.58211108442530
1984-01-01	27.81476932374530
1985-01-01	25.67310123917730
1986-01-01	15.10537542097950
1987-01-01	6.65244804962687
1988-01-01	8.26676574400909
1989-01-01	14.32953903285720
1990-01-01	21.96017511650830
1991-01-01	51.07109773043130
1992-01-01	77.29659295596510
1993-01-01	22.06994941852920
1994-01-01	35.06339424847720
1995-01-01	19.90874883641680
1996-01-01	26.40665660740430
1997-01-01	9.65755261268598
1998-01-01	8.63189613012140
1999-01-01	5.95423949113011
2000-01-01	8.17108356120222
2001-01-01	6.99062341611757
2002-01-01	7.07746603976979
2003-01-01	10.32207757733940
2004-01-01	13.62567734885280
2005-01-01	15.29604319879300
2006-01-01	8.59197612351486
2007-01-01	9.29325515699288
2008-01-01	22.02092769014520
2009-01-01	9.57378727761395
2010-01-01	12.60950823501950
2011-01-01	7.52969244333801
2012-01-01	6.89824818644853
2013-01-01	9.34440283355142
2014-01-01	8.29000577700750
2015-01-01	3.67588791857115
2016-01-01	2.34975849771445
2017-01-01	4.37889242901781