Year	Percent change
1980	42.82
1981	29.361
1982	20.532
1983	51.511
1984	66.125
1985	83.001
1986	70.652
1987	57.285
1988	69.007
1989	89.177
1990	128.954
1991	81.449
1992	58.911
1993	52.882
1994	44.091
1995	35.443
1996	24.328
1997	15.169
1998	8.615
1999	4.181
2000	5.035
2001	3.59
2002	25.956
2003	10.188
2004	7.587
2005	4.896
2006	6.38
2007	8.507
2008	9.2
2009	5.9
2010	6.929
2011	8.6
2012	7.477
2013	8.525
2014	8.258
2015	9.436
2016	8.103
2017	6.552
2018	7.96
2019	7.5
2020	7
2021	7
2022	7
2023	7
2024	7