Year	Number of Years
1960-01-01	45.4803743771465
1961-01-01	46.0815789998323
1962-01-01	46.6773442731220
1963-01-01	47.2681433988091
1964-01-01	47.8518782353065
1965-01-01	48.4197905551691
1966-01-01	48.9617202794276
1967-01-01	49.4713130661775
1968-01-01	49.9471550414240
1969-01-01	50.3944332278093
1970-01-01	50.8265133930907
1971-01-01	51.2614157161901
1972-01-01	51.7144115853300
1973-01-01	52.1948493890808
1974-01-01	52.7032727091248
1975-01-01	53.2361504607897
1976-01-01	53.7833910341503
1977-01-01	54.3285493476011
1978-01-01	54.8549071358132
1979-01-01	55.3519888323203
1980-01-01	55.8121422310812
1981-01-01	56.2445782426329
1982-01-01	56.6364262493571
1983-01-01	57.0071815532170
1984-01-01	57.3618352935471
1985-01-01	57.7041305814892
1986-01-01	58.0400973414598
1987-01-01	58.3891920706284
1988-01-01	58.7216868862794
1989-01-01	59.0656209879487
1990-01-01	59.4087457838064
1991-01-01	59.7256442016779
1992-01-01	60.0822291662065
1993-01-01	60.4133139441183
1994-01-01	60.7379217164681
1995-01-01	61.0570097280763
1996-01-01	61.3827870450061
1997-01-01	61.7157763693393
1998-01-01	62.0484285223140
1999-01-01	62.3669381464740
2000-01-01	62.6708877043104
2001-01-01	62.9961993048126
2002-01-01	63.3177638275614
2003-01-01	63.6487155741752
2004-01-01	63.9897744468645
2005-01-01	64.3364536175251
2006-01-01	64.6984217446825
2007-01-01	65.0668844081296
2008-01-01	65.4337907713218
2009-01-01	65.8124165630166
2010-01-01	66.1807943230881
2011-01-01	66.5226218606555
2012-01-01	66.8371695020695
2013-01-01	67.1313969626416
2014-01-01	67.3996051362059
2015-01-01	67.6473864012714
2016-01-01	67.8822078977277