Year	Percent of Total
1960-01-01	54.4492644354047
1961-01-01	54.1512706087273
1962-01-01	53.9884980646731
1963-01-01	53.9104949700791
1964-01-01	53.8551283800466
1965-01-01	53.7918724726571
1966-01-01	53.5469197414676
1967-01-01	53.3093453598530
1968-01-01	53.1051492506206
1969-01-01	52.9777765717404
1970-01-01	52.9402679808005
1971-01-01	52.6783956820987
1972-01-01	52.5461216944259
1973-01-01	52.5022359755960
1974-01-01	52.4961461231512
1975-01-01	52.5037019644113
1976-01-01	52.3605905026139
1977-01-01	52.2547330739478
1978-01-01	52.1801159871168
1979-01-01	52.1424146611877
1980-01-01	52.1450299196210
1981-01-01	51.9949040795726
1982-01-01	51.9026815904865
1983-01-01	51.8628503583768
1984-01-01	51.8692478894510
1985-01-01	51.9128431880675
1986-01-01	51.7754609178710
1987-01-01	51.7210917170079
1988-01-01	51.7224616444251
1989-01-01	51.7519813660410
1990-01-01	51.7971598525676
1991-01-01	51.7602506504324
1992-01-01	51.7608989304522
1993-01-01	51.7966941848620
1994-01-01	51.8729796913148
1995-01-01	51.9917496569268
1996-01-01	51.9451457451170
1997-01-01	51.9563891590950
1998-01-01	52.0118821993751
1999-01-01	52.0978273402349
2000-01-01	52.2064282057653
2001-01-01	52.2259759280497
2002-01-01	52.2897800980335
2003-01-01	52.3838663366303
2004-01-01	52.4961661491535
2005-01-01	52.6221443765594
2006-01-01	52.6854933006432
2007-01-01	52.7738538782297
2008-01-01	52.8874459607861
2009-01-01	53.0299119169157
2010-01-01	53.2017171240659
2011-01-01	53.3101675651371
2012-01-01	53.4575398533409
2013-01-01	53.6382883884005
2014-01-01	53.8444813635390
2015-01-01	54.0707696857752
2016-01-01	54.2934300231996
2017-01-01	54.5421920265423