Year	Percent change (Units)
1980	17.079
1981	15.451
1982	16.126
1983	7.445
1984	6.129
1985	15.380
1986	13.221
1987	15.762
1988	6.351
1989	5.716
1990	6.098
1991	2.602
1992	1.015
1993	1.288
1994	1.745
1995	3.755
1996	2.286
1997	1.187
1998	1.265
1999	-0.114
2000	2.615
2001	2.626
2002	2.677
2003	1.754
2004	2.290
2005	3.037
2006	3.365
2007	2.376
2008	3.959
2009	2.116
2010	2.302
2011	4.028
2012	1.060
2013	1.134
2014	1.228
2015	0.293
2016	0.646
2017	1.851
2018	1.598
2019	1.620
2020	1.715
2021	3.941
2022	7.172
2023	5.733
2024	3.094
2025	2.523
2026	2.370
2027	2.115
2028	1.964
2029	2.041