Year	Percent change (Units)
1980	-9.000
1981	2.006
1982	1.812
1983	6.601
1984	4.957
1985	-2.337
1986	35.114
1987	19.243
1988	11.702
1989	13.428
1990	12.436
1991	20.054
1992	3.785
1993	7.528
1994	23.038
1995	20.740
1996	13.363
1997	1.435
1998	-26.993
1999	29.465
2000	23.103
2001	-4.372
2002	14.865
2003	11.656
2004	10.743
2005	6.749
2006	12.705
2007	10.244
2008	3.093
2009	-7.240
2010	19.286
2011	17.726
2012	2.124
2013	1.218
2014	0.283
2015	0.673
2016	3.913
2017	8.849
2018	2.019
2019	-2.508
2020	0.348
2021	12.553
2022	4.332
2023	-0.621
2024	2.424
2025	3.456
2026	3.354
2027	3.215
2028	3.143
2029	3.124