Year	Percent change (Units)
1980	11.000
1981	-0.844
1982	-8.491
1983	10.146
1984	-14.743
1985	-21.024
1986	11.835
1987	4.090
1988	-4.383
1989	17.785
1990	8.596
1991	9.884
1992	20.893
1993	5.675
1994	-7.809
1995	12.241
1996	6.077
1997	2.755
1998	21.087
1999	-4.368
2000	5.986
2001	17.779
2002	5.529
2003	2.337
2004	3.367
2005	-7.988
2006	-23.970
2007	1.594
2008	4.860
2009	16.388
2010	16.263
2011	-1.223
2012	-2.943
2013	10.836
2014	-3.752
2015	8.136
2016	8.057
2017	1.308
2018	10.638
2019	1.526
2020	-1.334
2021	14.011
2022	3.448
2023	-12.542
2024	3.435
2025	2.452
2026	2.036
2027	3.468
2028	2.243
2029	4.432