Year	Percent change (Units)
1980	28.442
1981	28.442
1982	28.442
1983	28.442
1984	28.442
1985	28.442
1986	28.442
1987	28.442
1988	28.442
1989	28.442
1990	44.064
1991	11.840
1992	17.775
1993	20.370
1994	18.296
1995	10.533
1996	8.176
1997	6.199
1998	14.644
1999	5.404
2000	8.644
2001	8.215
2002	14.660
2003	9.361
2004	2.714
2005	9.959
2006	12.384
2007	6.086
2008	7.442
2009	1.876
2010	7.224
2011	4.888
2012	4.030
2013	3.753
2014	4.201
2015	3.135
2016	3.909
2017	4.493
2018	3.200
2019	2.810
2020	2.168
2021	6.827
2022	8.117
2023	3.674
2024	4.000
2025	4.000
2026	4.000
2027	4.000
2028	4.000
2029	4.000