Year	Percent
1960-01-01	39.4938246992083
1961-01-01	39.4009632125984
1962-01-01	39.9793161344488
1963-01-01	40.3578367226635
1964-01-01	40.8424594514556
1965-01-01	41.7897141096582
1966-01-01	43.3182669460577
1967-01-01	44.1512207207908
1968-01-01	44.9173317323181
1969-01-01	46.1569547385879
1970-01-01	46.3318468855614
1971-01-01	45.9017922906782
1972-01-01	46.7585857303060
1973-01-01	48.1207576511975
1974-01-01	48.9511624866771
1975-01-01	48.3925263943599
1976-01-01	49.8792711378921
1977-01-01	51.4019844190393
1978-01-01	53.6787855443493
1979-01-01	55.0535097159591
1980-01-01	55.4103198078735
1981-01-01	55.8680901748797
1982-01-01	55.6023060158873
1983-01-01	56.1615626681223
1984-01-01	58.0571393833357
1985-01-01	59.2885677825221
1986-01-01	60.4519268817035
1987-01-01	61.9088732588530
1988-01-01	63.0082313145841
1989-01-01	64.0752351340919
1990-01-01	64.0432406308772
1991-01-01	63.3276328600409
1992-01-01	63.5500932323365
1993-01-01	63.9971725548214
1994-01-01	65.2190767922304
1995-01-01	65.7710377704427
1996-01-01	66.2871117071458
1997-01-01	67.1365600305036
1998-01-01	67.4146003289183
1999-01-01	67.6423586931624
2000-01-01	67.7889680389835
2001-01-01	67.0934607196543
2002-01-01	66.0868035247054
2003-01-01	65.6811831625639
2004-01-01	65.3891835058776
2005-01-01	65.6133331428583
2006-01-01	66.0506692334950
2007-01-01	65.9232773135716
2008-01-01	65.4968790241571
2009-01-01	63.4008826798205
2010-01-01	62.4268976442999
2011-01-01	62.0131260530528
2012-01-01	62.1941784450957
2013-01-01	62.3433750763936
2014-01-01	62.9986052979095
2015-01-01	63.4203723845302
2016-01-01	64.0471358643466
2017-01-01	64.9453336944040