Year	Percent change (Units)
1980	13.400
1981	3.592
1982	-5.918
1983	5.305
1984	-15.064
1985	-26.816
1986	-5.540
1987	16.739
1988	10.141
1989	7.718
1990	14.333
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	6.152
2002	6.422
2003	7.546
2004	-1.706
2005	-5.564
2006	-20.170
2007	7.965
2008	12.663
2009	7.209
2010	12.683
2011	-19.145
2012	-2.384
2013	11.754
2014	0.399
2015	2.662
2016	8.253
2017	7.272
2018	4.602
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