Year	Percent change (Units)
1980	9.169
1981	10.495
1982	2.048
1983	17.569
1984	19.158
1985	1.880
1986	28.045
1987	22.165
1988	5.209
1989	4.201
1990	0.878
1991	13.337
1992	6.853
1993	5.187
1994	7.370
1995	13.334
1996	6.915
1997	9.187
1998	0.631
1999	14.241
2000	18.861
2001	-8.878
2002	11.343
2003	12.135
2004	13.889
2005	5.350
2006	12.361
2007	9.293
2008	3.263
2009	-10.541
2010	28.048
2011	5.977
2012	22.084
2013	0.572
2014	1.523
2015	-2.826
2016	-5.614
2017	6.739
2018	-0.675
2019	1.468
2020	3.600
2021	18.754
2022	-2.045
2023	-2.523
2024	3.912
2025	3.756
2026	3.621
2027	2.170
2028	3.593
2029	3.482