Year	Percent change (Units)
1980	10.162
1981	19.719
1982	2.218
1983	-4.052
1984	-8.873
1985	10.122
1986	16.900
1987	-2.423
1988	-20.420
1989	-16.165
1990	10.106
1991	3.441
1992	-19.402
1993	0.807
1994	3.045
1995	-5.668
1996	13.233
1997	19.547
1998	13.533
1999	0.842
2000	14.865
2001	16.418
2002	-4.208
2003	9.418
2004	0.370
2005	12.526
2006	6.028
2007	22.483
2008	5.332
2009	-9.970
2010	2.736
2011	14.061
2012	1.805
2013	4.131
2014	12.707
2015	1.836
2016	-5.658
2017	-1.481
2018	4.152
2019	24.798
2020	-13.380
2021	18.217
2022	-10.223
2023	11.303
2024	4.974
2025	5.484
2026	4.519
2027	3.289
2028	4.218
2029	6.282