Year	Percent of Total
1960-01-01	23.0999022862069
1961-01-01	23.1629607175625
1962-01-01	23.1453341000871
1963-01-01	23.0420571760488
1964-01-01	22.8875279610047
1965-01-01	22.7124076640039
1966-01-01	22.5846694258257
1967-01-01	22.4283586445277
1968-01-01	22.2659273794308
1969-01-01	22.1245929294084
1970-01-01	22.0160682016348
1971-01-01	21.9037126467080
1972-01-01	21.8411362213109
1973-01-01	21.8006665851491
1974-01-01	21.7336527547259
1975-01-01	21.6213726458150
1976-01-01	21.6654874691071
1977-01-01	21.6342807514982
1978-01-01	21.5774479757239
1979-01-01	21.5654568100868
1980-01-01	21.6240650662355
1981-01-01	21.6227399514649
1982-01-01	21.7140625240765
1983-01-01	21.8557099279349
1984-01-01	21.9810230154996
1985-01-01	22.0624449470145
1986-01-01	22.1594848548176
1987-01-01	22.2369920732745
1988-01-01	22.2889517399399
1989-01-01	22.2871632660731
1990-01-01	22.1833428952200
1991-01-01	22.0672193461502
1992-01-01	21.8023947764678
1993-01-01	21.4224032783646
1994-01-01	21.0064148273309
1995-01-01	20.6164725782680
1996-01-01	19.8997556667814
1997-01-01	19.2816920791616
1998-01-01	18.7324634692644
1999-01-01	18.1778743101705
2000-01-01	17.5829383208778
2001-01-01	17.0384464216812
2002-01-01	16.4936516982322
2003-01-01	15.9627477130677
2004-01-01	15.5025246321224
2005-01-01	15.1567368520442
2006-01-01	15.0067776034483
2007-01-01	14.9250188977971
2008-01-01	14.9290295227631
2009-01-01	15.0064005150356
2010-01-01	15.1331504644539
2011-01-01	15.3392414763382
2012-01-01	15.5199428801737
2013-01-01	15.6975090045098
2014-01-01	15.8996145966311
2015-01-01	16.1305111071746
2016-01-01	16.1956871236977
2017-01-01	16.3675750134389