Year	Number of Years
1960-01-01	63.3957935162320
1961-01-01	63.9158470985132
1962-01-01	64.3093713668292
1963-01-01	64.6734702000171
1964-01-01	64.9709169161421
1965-01-01	65.1944954273015
1966-01-01	65.3625814246908
1967-01-01	65.4797690689710
1968-01-01	65.6216801683157
1969-01-01	65.7059470863128
1970-01-01	65.9492028290004
1971-01-01	66.1518810790900
1972-01-01	66.1940695036840
1973-01-01	66.3023786884473
1974-01-01	66.4057071922375
1975-01-01	66.2238500826718
1976-01-01	66.2049920227177
1977-01-01	66.2115889906545
1978-01-01	66.2780748373810
1979-01-01	66.2199415701092
1980-01-01	66.3451558419168
1981-01-01	66.5602731845920
1982-01-01	66.8940092958188
1983-01-01	67.0139093097087
1984-01-01	67.0087740878674
1985-01-01	67.4185373292981
1986-01-01	68.1761365877744
1987-01-01	68.3470035303971
1988-01-01	68.4206933453851
1989-01-01	68.3738599709620
1990-01-01	68.2489532406420
1991-01-01	68.0055464279558
1992-01-01	67.3648664375400
1993-01-01	66.5060596289137
1994-01-01	66.2601210875502
1995-01-01	66.3121670365753
1996-01-01	66.8081817893408
1997-01-01	67.4157578167385
1998-01-01	67.7506563674979
1999-01-01	67.6058173986822
2000-01-01	67.6641686329781
2001-01-01	67.8322971981389
2002-01-01	67.8542547675177
2003-01-01	67.9861887631274
2004-01-01	68.3107728285698
2005-01-01	68.4469207099653
2006-01-01	69.0683431903758
2007-01-01	69.5774815860247
2008-01-01	69.8710004576859
2009-01-01	70.4705462438662
2010-01-01	70.7741392561805
2011-01-01	71.3417600794036
2012-01-01	71.6682039260765
2013-01-01	72.0627234831536
2014-01-01	72.2654704208553
2015-01-01	72.5357946123155
2016-01-01	72.8147231428680