Year	Number of Years
1960-01-01	56.1280731707317
1961-01-01	56.5641219512195
1962-01-01	57.0026585365854
1963-01-01	57.4431951219512
1964-01-01	57.8822439024390
1965-01-01	58.3152682926829
1966-01-01	58.7382926829268
1967-01-01	59.1463170731707
1968-01-01	59.5358536585366
1969-01-01	59.9038780487805
1970-01-01	60.2449024390244
1971-01-01	60.5544146341463
1972-01-01	60.8354146341464
1973-01-01	61.0929024390244
1974-01-01	61.3329024390244
1975-01-01	61.5648536585366
1976-01-01	61.7972439024390
1977-01-01	62.0400731707317
1978-01-01	62.3009024390244
1979-01-01	62.5857560975610
1980-01-01	62.9037804878049
1981-01-01	63.2636341463415
1982-01-01	63.6588780487805
1983-01-01	64.0775121951220
1984-01-01	64.5049268292683
1985-01-01	64.9189512195122
1986-01-01	65.2937804878049
1987-01-01	65.6111951219512
1988-01-01	65.8585853658537
1989-01-01	67.9073170731707
1990-01-01	68.2975609756098
1991-01-01	68.5512195121951
1992-01-01	68.1024390243903
1993-01-01	67.1926829268293
1994-01-01	66.0390243902439
1995-01-01	65.7902439024390
1996-01-01	66.5439024390244
1997-01-01	66.8926829268293
1998-01-01	67.0512195121951
1999-01-01	68.6560975609756
2000-01-01	68.5585365853659
2001-01-01	68.7073170731707
2002-01-01	68.1560975609756
2003-01-01	68.2560975609756
2004-01-01	68.1536585365854
2005-01-01	67.9560975609756
2006-01-01	67.6951219512195
2007-01-01	67.8951219512195
2008-01-01	68.4512195121951
2009-01-01	69.1024390243903
2010-01-01	69.3000000000000
2011-01-01	69.6024390243903
2012-01-01	70.0024390243902
2013-01-01	70.2024390243902
2014-01-01	70.4024390243902
2015-01-01	70.6512195121951
2016-01-01	70.9512195121951