Year	Percent
1960-01-01	5.42199785570440
1961-01-01	6.47659379477342
1962-01-01	5.23784589584948
1963-01-01	5.28491946118914
1964-01-01	4.66200179120559
1965-01-01	3.99289040823147
1966-01-01	3.20831897652314
1967-01-01	3.08877166246138
1968-01-01	2.86687114147793
1969-01-01	2.81988502338713
1970-01-01	4.41281258642832
1971-01-01	5.43063369786127
1972-01-01	5.02788536212847
1973-01-01	4.21502374854159
1974-01-01	4.92918416121584
1975-01-01	7.98200101505365
1976-01-01	7.13097528578291
1977-01-01	6.32608113818671
1978-01-01	5.31463393199279
1979-01-01	5.19732681313591
1980-01-01	7.06171201402995
1981-01-01	7.53006183167547
1982-01-01	10.08410231270550
1983-01-01	10.12118953409210
1984-01-01	7.56652539718117
1985-01-01	7.13156396914696
1986-01-01	7.03476481801625
1987-01-01	6.30594370596317
1988-01-01	5.55466143406382
1989-01-01	5.27409790116608
1990-01-01	5.74193687412839
1991-01-01	7.26256342742851
1992-01-01	8.03418315934376
1993-01-01	7.29977574831300
1994-01-01	6.24124208039372
1995-01-01	5.62610855448010
1996-01-01	5.45191642438364
1997-01-01	4.94703915850768
1998-01-01	4.46053542217483
1999-01-01	4.15245609472894
2000-01-01	3.92091624393707
2001-01-01	4.86121008144836
2002-01-01	6.01817495275852
2003-01-01	6.35398588239991
2004-01-01	5.71455717757066
2005-01-01	5.13891235208396
2006-01-01	4.69273266966942
2007-01-01	4.78101175497734
2008-01-01	6.17033264724302
2009-01-01	10.45961773942630
2010-01-01	10.68602343610020
2011-01-01	9.52172887494358
2012-01-01	8.34139487759776
2013-01-01	7.75887811186326
2014-01-01	6.36380480151417
2015-01-01	5.46684033022294
2016-01-01	5.01676654434263
2017-01-01	4.46512873045869