Year	Percent change (Units)
1980	3.021
1981	5.557
1982	-20.674
1983	4.785
1984	9.884
1985	-27.987
1986	-8.255
1987	-34.075
1988	-2.960
1989	-7.285
1990	-4.935
1991	10.031
1992	4.291
1993	-4.670
1994	5.223
1995	14.054
1996	9.566
1997	4.402
1998	-10.025
1999	5.889
2000	-29.328
2001	-33.958
2002	-7.315
2003	18.375
2004	23.654
2005	9.210
2006	8.020
2007	4.719
2008	15.605
2009	-13.200
2010	27.814
2011	35.311
2012	22.943
2013	5.013
2014	3.367
2015	2.841
2016	-4.387
2017	12.842
2018	13.058
2019	-14.885
2020	-28.449
2021	-13.258
2022	-2.606
2023	32.135
2024	-10.597
2025	10.176
2026	6.478
2027	6.054
2028	2.339
2029	2.358