Year	Percent
1960	5.53684
1961	4.49669
1962	5.94781
1963	5.11445
1964	4.694
1965	7.02488
1966	11.90199
1967	16.46824
1968	18.21772
1969	13.1618
1970	11.29328
1971	13.6207
1972	12.58045
1973	14.01013
1974	13.70416
1975	23.94745
1976	27.53691
1977	29.53294
1978	54.36857
1979	35.64399
1980	28.04692
1981	29.80366
1982	27.09179
1983	29.49689
1984	27.44916
1985	30.82374
1986	33.48503
1987	27.52608
1988	35.8899
1989	35.67054
1990	34.53216
1991	35.86524
1992	21.67534
1993	20.60871
1994	16.18188
1995	14.06247
1996	10.31639
1997	6.89584
1998	8.09803
1999	4.25891
2000	4.85757
2001	7.67433
2002	6.48836
2003	12.64859
2004	7.8257
2005	15.88037
2006	8.65714
2007	5.6015
2008	5.65628
2009	5.90053
2015	1.52491
2016	1.1641
2017	0.84329
2018	-0.68757
2019	0.63155
2020	0.78268
2021	0.4732