Year	Percent change
1980	35.138
1981	19.687
1982	9.941
1983	27.257
1984	19.86
1985	30.703
1986	19.477
1987	19.881
1988	14.684
1989	17.028
1990	26.036
1991	21.815
1992	15.454
1993	12.743
1994	11.46
1995	8.229
1996	7.356
1997	6.127
1998	5.106
1999	3.333
2000	3.838
2001	3.565
2002	2.486
2003	2.811
2004	1.053
2005	3.053
2006	3.402
2007	4.413
2008	8.723
2009	1.498
2010	1.408
2011	3.335
2012	2.999
2013	1.789
2014	4.714
2015	4.349
2016	3.788
2017	2.183
2018	2.318
2019	2.336
2020	2.968
2021	3.001
2022	3.001
2023	3.001
2024	3.001