Year	Percent change (Units)
1980	99.203
1981	100.000
1982	100.000
1983	150.000
1984	16.711
1985	100.000
1986	143.800
1987	215.400
1988	166.700
1989	130.800
1990	45.400
1991	20.819
1992	42.248
1993	29.969
1994	5.850
1995	6.787
1996	7.516
1997	7.729
1998	5.834
1999	5.759
2000	3.382
2001	1.922
2002	-0.300
2003	8.710
2004	3.666
2005	8.602
2006	7.219
2007	6.090
2008	12.044
2009	13.017
2010	3.983
2011	18.659
2012	14.011
2013	5.467
2014	4.290
2015	3.692
2016	5.169
2017	5.576
2018	2.549
2019	2.137
2020	2.758
2021	2.207
2022	7.192
2023	5.352
2024	3.810
2025	4.873
2026	5.036
2027	5.000
2028	5.000
2029	5.000