Year	Percent change (Units)
1980	-21.798
1981	-2.425
1982	-4.189
1983	5.198
1984	11.168
1985	10.100
1986	-6.300
1987	5.400
1988	35.696
1989	-8.345
1990	-2.014
1991	29.272
1992	0.695
1993	7.317
1994	1.000
1995	12.986
1996	-11.637
1997	20.279
1998	-6.080
1999	4.005
2000	14.766
2001	5.968
2002	0.549
2003	5.566
2004	2.922
2005	9.181
2006	10.179
2007	11.572
2008	-5.124
2009	-10.507
2010	8.364
2011	4.808
2012	-0.268
2013	6.520
2014	-1.762
2015	13.197
2016	2.857
2017	-0.442
2018	1.585
2019	3.559
2020	-10.618
2021	25.484
2022	-0.434
2023	0.122
2024	4.860
2025	3.085
2026	3.184
2027	3.652
2028	3.372
2029	3.404