Year	Percent change (Units)
1980	5.756
1981	-0.806
1982	-19.846
1983	1.749
1984	10.527
1985	-3.295
1986	-5.241
1987	-1.042
1988	-11.939
1989	8.326
1990	18.457
1991	-29.608
1992	7.522
1993	4.385
1994	2.811
1995	30.849
1996	2.520
1997	14.454
1998	1.562
1999	-9.400
2000	27.525
2001	23.497
2002	10.671
2003	18.442
2004	24.941
2005	19.743
2006	26.974
2007	41.901
2008	10.833
2009	-21.436
2010	12.998
2011	9.730
2012	-1.722
2013	9.265
2014	8.775
2015	8.509
2016	16.588
2017	11.399
2018	8.615
2019	8.614
2020	-5.213
2021	14.736
2022	9.939
2023	-1.425
2024	5.726
2025	6.613
2026	6.072
2027	5.078
2028	4.856
2029	4.459