Year	Number of Years
1960-01-01	40.3770124521921
1961-01-01	40.8169239695851
1962-01-01	41.2474883349662
1963-01-01	41.6669177928675
1964-01-01	42.0763403652582
1965-01-01	42.4778391720293
1966-01-01	42.8759883072861
1967-01-01	43.2754894684987
1968-01-01	43.6793484880748
1969-01-01	44.0884227155690
1970-01-01	44.5027721150378
1971-01-01	44.9215711083438
1972-01-01	45.3400587623411
1973-01-01	45.7528764478611
1974-01-01	46.1555530910984
1975-01-01	46.5439113605504
1976-01-01	46.9150058993011
1977-01-01	47.2692565722298
1978-01-01	47.6065948231844
1979-01-01	47.9270213098064
1980-01-01	48.2311206089088
1981-01-01	48.5202584024415
1982-01-01	48.7942494080561
1983-01-01	49.0510792116044
1984-01-01	49.2869945200058
1985-01-01	49.4924411347884
1986-01-01	49.6562343955787
1987-01-01	49.7721384694731
1988-01-01	49.8407559249805
1989-01-01	49.8706904800838
1990-01-01	49.8747298094765
1991-01-01	49.8704215933773
1992-01-01	49.8693027435812
1993-01-01	49.8784572311912
1994-01-01	49.8966181335012
1995-01-01	49.9243392312152
1996-01-01	49.9663399566146
1997-01-01	50.0340951403479
1998-01-01	50.1408521996318
1999-01-01	50.3020081994020
2000-01-01	50.5370102327547
2001-01-01	50.8636115362955
2002-01-01	51.2888019862551
2003-01-01	51.8108993089119
2004-01-01	52.4218238125597
2005-01-01	53.1094567686804
2006-01-01	53.8575544350960
2007-01-01	54.6395784708758
2008-01-01	55.4282316735759
2009-01-01	56.2025929013263
2010-01-01	56.9422825611616
2011-01-01	57.6353031380482
2012-01-01	58.2824128818917
2013-01-01	58.8831983010980
2014-01-01	59.4352273964709
2015-01-01	59.9378095222685
2016-01-01	60.3935627977383