Year	Percent of Total
1960-01-01	50.5746002780674
1961-01-01	49.9149974129648
1962-01-01	49.4680851063830
1963-01-01	49.1294277385089
1964-01-01	48.8614423347466
1965-01-01	48.6519850356675
1966-01-01	48.5463707280492
1967-01-01	48.4550811060235
1968-01-01	48.4133343672724
1969-01-01	48.4567461282398
1970-01-01	48.5906270972811
1971-01-01	48.2991834477895
1972-01-01	48.0684231222965
1973-01-01	47.9055485946757
1974-01-01	47.8146633462039
1975-01-01	47.7952874080744
1976-01-01	47.8501187595729
1977-01-01	48.0221039645519
1978-01-01	48.3222394128018
1979-01-01	48.6628215562082
1980-01-01	48.9563317262669
1981-01-01	49.5486765244026
1982-01-01	49.9676567656766
1983-01-01	50.2830152353326
1984-01-01	50.6189701085770
1985-01-01	51.0401950024557
1986-01-01	51.1924419701830
1987-01-01	51.4806103717302
1988-01-01	51.8265299282794
1989-01-01	52.1434138737335
1990-01-01	52.4099982938065
1991-01-01	52.5328840660088
1992-01-01	52.5702846379884
1993-01-01	52.5974617439883
1994-01-01	52.6775885835557
1995-01-01	52.8181365751366
1996-01-01	53.3971994983059
1997-01-01	54.0206492603991
1998-01-01	54.5760886557468
1999-01-01	55.0086601457582
2000-01-01	55.3508683258193
2001-01-01	55.7678128823769
2002-01-01	56.1806365987049
2003-01-01	56.6265373611266
2004-01-01	57.1275929138792
2005-01-01	57.6862929217692
2006-01-01	58.2595865133604
2007-01-01	58.8414480893545
2008-01-01	59.4186141459670
2009-01-01	59.9718407665428
2010-01-01	60.4885450610682
2011-01-01	61.2183771173054
2012-01-01	61.8830950903027
2013-01-01	62.5182680043349
2014-01-01	63.1520583234289
2015-01-01	63.7833715570795
2016-01-01	64.2423846040648
2017-01-01	64.7265273659460