Year	Percent change
1980	55.701
1981	49.29
1982	59.866
1983	76.645
1984	18.816
1985	35.936
1986	13.507
1987	24.44
1988	20.607
1989	25.205
1990	7.221
1991	7.527
1992	1.507
1993	4.751
1994	0.525
1995	1.995
1996	2.058
1997	2.047
1998	1.278
1999	5.534
2000	4.14
2001	8.657
2002	1.951
2003	2.759
2004	3.919
2005	4.13
2006	6.971
2007	5.859
2008	18.132
2009	7.489
2010	2.479
2011	5.251
2012	4.203
2013	4.14
2014	0.827
2015	2.012
2016	1.893
2017	1.874
2018	3.736
2019	2.6
2020	2.6
2021	2.5
2022	2.5
2023	2.5
2024	2.5