Year	Percent
1960	5.65567
1961	3.65199
1962	13.38041
1963	16.15407
1964	83.87815
1965	93.78649
1966	62.09491
1967	49.24873
1968	45.66917
1969	40.00335
1970	43.50568
1971	34.8347
1972	46.22858
1973	34.9103
1974	37.78761
1975	44.25238
1976	34.5659
1977	31.79044
1978	35.3484
1979	24.59349
1980	9.4718
1981	13.71676
1982	19.04583
1983	14.86985
1984	14.33799
1985	25.87776
1986	34.74952
1987	41.15666
1988	52.72388
1989	26.83311
1990	28.07754
1991	45.58513
1992	26.96373
1993	23.4714
1994	24.88563
1995	87.93895
1996	75.4957
1997	193.55894
1998	89.90549
1999	68.90887
2000	58.75127
2001	47.46537
2002	63.6933
2003	62.35552
2004	116.92213
2005	80.90142
2006	60.38334
2007	39.67303
2008	20.38708
2009	12.13856
2010	17.69082
2011	16.58137
2012	15.77876
2013	24.33742
2014	28.4787
2015	37.41568
2016	32.05436
2017	37.40533
2018	26.50333
2019	22.8882
2020	56.15921
2021	47.69576