Year	Percent of Total
1960-01-01	42.6891894356424
1961-01-01	43.2306040622042
1962-01-01	43.7888965218702
1963-01-01	44.3018716192041
1964-01-01	44.6781818272321
1965-01-01	44.8892380215135
1966-01-01	45.2369354551207
1967-01-01	45.4065727223362
1968-01-01	45.4472035691916
1969-01-01	45.4352060889224
1970-01-01	45.4163850368862
1971-01-01	45.5979934446607
1972-01-01	45.7238916192335
1973-01-01	45.8054298509498
1974-01-01	45.8470713797582
1975-01-01	45.8550963165029
1976-01-01	46.0291178343101
1977-01-01	46.1403892193258
1978-01-01	46.1960667384509
1979-01-01	46.2013168868877
1980-01-01	46.1624222327335
1981-01-01	46.2523623826751
1982-01-01	46.2637028354272
1983-01-01	46.2164997015555
1984-01-01	46.1314798925904
1985-01-01	46.0193600732151
1986-01-01	45.9961920843267
1987-01-01	45.9396131803947
1988-01-01	45.8471503264811
1989-01-01	45.7183100241395
1990-01-01	45.5625762104896
1991-01-01	45.5344755706337
1992-01-01	45.4612490870910
1993-01-01	45.3602315024465
1994-01-01	45.2549461628833
1995-01-01	45.1610193389435
1996-01-01	45.2060277839796
1997-01-01	45.2300741281588
1998-01-01	45.2348270699478
1999-01-01	45.2111794906089
2000-01-01	45.1521443214307
2001-01-01	45.1738559634835
2002-01-01	45.1224825928742
2003-01-01	45.0170063430815
2004-01-01	44.8776630137049
2005-01-01	44.7119398208753
2006-01-01	44.5321909625435
2007-01-01	44.3398451222663
2008-01-01	44.1193642737625
2009-01-01	43.8486603292382
2010-01-01	43.5222233358737
2011-01-01	43.2052337871101
2012-01-01	42.8327958832882
2013-01-01	42.4278213291270
2014-01-01	42.0248140287407
2015-01-01	41.6433785335763
2016-01-01	41.2934179853254
2017-01-01	40.9696336401209