Year	Percent change
1981	26.29
1982	23.404
1983	34.483
1984	27.564
1985	39.196
1986	28.52
1987	32.303
1988	30.786
1989	36.851
1990	18.624
1991	37.76
1992	20.736
1993	26.108
1994	37.972
1995	26.771
1996	15.546
1997	15.353
1998	11.26
1999	6.962
2000	5.529
2001	4.854
2002	4.404
2003	4.563
2004	4.102
2005	4.982
2006	6.659
2007	6.423
2008	13.474
2009	12.226
2010	5.553
2011	19.754
2012	12.062
2013	5.561
2014	4.752
2015	6.838
2016	5.04
2017	3.97
2018	3.251
2019	4.087
2020	4.903
2021	4.903
2022	4.903
2023	4.903
2024	4.903