Year	Percent
1967	51.09614
1968	52.3294
1969	33.79396
1970	37.25086
1971	39.64724
1972	23.96831
1973	20.52017
1974	15.00951
1975	10.79529
1976	8.33108
1977	5.42231
1978	5.924
1979	6.65819
1980	6.19316
1981	5.27373
1982	4.39445
1983	3.08286
1984	3.14209
1985	2.73315
1986	3.16759
1987	5.83503
1988	6.36278
1989	6.10188
1990	4.58734
1991	4.82046
1992	4.96834
1993	4.19844
1994	2.87756
1995	2.03509
1996	1.47238
1997	1.21976
1998	4.83452
1999	6.88011
2000	4.48223
2001	4.03218
2002	3.09463
2003	2.89298
2004	0.1579
2005	3.47141
2006	1.32824
2007	0.68428
2008	0.80723
2009	0.53992
2010	0.53318
2011	0.12158
2012	0.02144
2013	0.0225
2014	-0.12392
2015	-0.00971
2016	-0.03432
2017	0.08184
2018	0.26718
2019	-0.18341
2020	0.3532
2021	0.16411