Year	Percent
1960-01-01	3.046592778327020
1961-01-01	1.548996969898720
1962-01-01	2.662064179347700
1963-01-01	2.021582727597870
1964-01-01	3.444898482227660
1965-01-01	3.424927777455650
1966-01-01	5.039267218581860
1967-01-01	5.526476007530990
1968-01-01	6.081361711486150
1969-01-01	8.782771055541110
1970-01-01	6.380144490016770
1971-01-01	11.946898365405600
1972-01-01	10.663355975947700
1973-01-01	12.974608523933300
1974-01-01	25.082777858952700
1975-01-01	15.271685751848400
1976-01-01	21.141904803195500
1977-01-01	31.016749098880600
1978-01-01	21.038772359938300
1979-01-01	21.899224806201600
1980-01-01	15.867480383609400
1981-01-01	19.040410746691400
1982-01-01	21.679283727709500
1983-01-01	24.002762380291700
1984-01-01	28.384638889710300
1985-01-01	19.461410007869600
1986-01-01	12.331333489721800
1987-01-01	9.634831862457610
1988-01-01	10.101632115226500
1989-01-01	12.686303645614900
1990-01-01	13.630570569307400
1991-01-01	11.849484177367500
1992-01-01	9.559260331775120
1993-01-01	6.783779946654110
1994-01-01	5.420440192416230
1995-01-01	4.222816140994860
1996-01-01	3.068977325097910
1997-01-01	2.336862983141120
1998-01-01	2.572752259091270
1999-01-01	2.340094903121740
2000-01-01	2.853030392871560
2001-01-01	4.369903305517950
2002-01-01	3.600346582909110
2003-01-01	3.218990906828970
2004-01-01	2.365362040973000
2005-01-01	2.277163948878330
2006-01-01	3.107665458710540
2007-01-01	2.453965281387390
2008-01-01	2.588506576579640
2009-01-01	-0.835530021504170
2010-01-01	1.402572898953710
2011-01-01	3.653011004307290
2012-01-01	2.773338540515790
2013-01-01	0.274416666666680
2014-01-01	-0.278153367467421
2015-01-01	0.487938623904736
2016-01-01	0.607397074641661
2017-01-01	1.368614116434810