Year	Percent
1961-01-01	11.2753
1962-01-01	12.3186
1963-01-01	14.4205
1964-01-01	15.5638
1965-01-01	16.1847
1966-01-01	17.5969
1967-01-01	19.1187
1968-01-01	20.1571
1969-01-01	21.8454
1970-01-01	23.5767
1971-01-01	22.6936
1972-01-01	22.9003
1973-01-01	20.4809
1974-01-01	17.1013
1975-01-01	22.6973
1976-01-01	23.3038
1977-01-01	27.2546
1978-01-01	27.2546
1979-01-01	34.8028
1980-01-01	40.6606
1981-01-01	41.8046
1982-01-01	37.7528
1983-01-01	36.6901
1984-01-01	38.7606
1985-01-01	20.6725
1986-01-01	20.6725
1987-01-01	20.6725
1988-01-01	48.6215
1989-01-01	50.6840
1990-01-01	43.0343
1991-01-01	36.6709
1992-01-01	36.2800
1993-01-01	30.7156
1994-01-01	30.8429
1995-01-01	30.4291
1996-01-01	28.3165
1997-01-01	31.3183
1998-01-01	34.5935
1999-01-01	31.8095
2000-01-01	29.2491
2001-01-01	31.9462
2002-01-01	30.8744
2003-01-01	32.2964
2004-01-01	33.0904
2005-01-01	34.7104
2006-01-01	38.6345
2007-01-01	40.1445
2008-01-01	41.4543
2009-01-01	45.4183
2010-01-01	47.2328
2011-01-01	44.7218
2012-01-01	48.3438
2013-01-01	48.9967
2014-01-01	54.2051
2015-01-01	72.5562
2016-01-01	80.0423