Year	Percent of Total
1960-01-01	46.4419485882094
1961-01-01	46.6273591085785
1962-01-01	46.7857428364557
1963-01-01	46.8939116258307
1964-01-01	46.9253320449162
1965-01-01	46.8729234923768
1966-01-01	46.8662617406357
1967-01-01	46.7593251090731
1968-01-01	46.5691534283639
1969-01-01	46.3042085864535
1970-01-01	45.9598349410946
1971-01-01	45.6248513509605
1972-01-01	45.1559336293656
1973-01-01	44.5993968870478
1974-01-01	44.0234127358036
1975-01-01	43.4674344072678
1976-01-01	42.7905393137084
1977-01-01	42.2434408447409
1978-01-01	41.7519345399919
1979-01-01	41.2151181300305
1980-01-01	40.5997101438826
1981-01-01	40.1405046963822
1982-01-01	39.5564781703427
1983-01-01	38.9290477538825
1984-01-01	38.3698220822175
1985-01-01	37.9211089702695
1986-01-01	37.5410201827762
1987-01-01	37.2323319976519
1988-01-01	36.9670090265404
1989-01-01	36.6903018530210
1990-01-01	36.3721586685639
1991-01-01	36.0054307435001
1992-01-01	35.6363855105766
1993-01-01	35.2447127749207
1994-01-01	34.8106918680843
1995-01-01	34.3262937210821
1996-01-01	33.8396886670302
1997-01-01	33.2808286086025
1998-01-01	32.6805493654978
1999-01-01	32.0889285815547
2000-01-01	31.5326409358212
2001-01-01	30.9533464284204
2002-01-01	30.4387701954160
2003-01-01	29.9591259293031
2004-01-01	29.4663560758347
2005-01-01	28.9391233128294
2006-01-01	28.4696554102611
2007-01-01	27.9447833322201
2008-01-01	27.3960645985804
2009-01-01	26.8715416648529
2010-01-01	26.3919277839410
2011-01-01	25.9170011984921
2012-01-01	25.4925532953048
2013-01-01	25.0986138790035
2014-01-01	24.7017408448053
2015-01-01	24.2867705922057
2016-01-01	23.8878114608965
2017-01-01	23.4793897926277