Year	Percent change (Units)
1980	13.163
1981	25.397
1982	18.987
1983	33.511
1984	21.514
1985	16.721
1986	10.393
1987	8.906
1988	11.916
1989	11.482
1990	14.045
1991	9.323
1992	8.048
1993	5.908
1994	3.873
1995	3.392
1996	2.839
1997	2.078
1998	2.821
1999	1.697
2000	3.824
2001	3.911
2002	4.022
2003	2.280
2004	2.568
2005	2.540
2006	2.523
2007	2.742
2008	0.842
2009	-0.141
2010	2.444
2011	3.498
2012	2.090
2013	0.171
2014	-0.270
2015	0.291
2016	0.881
2017	1.618
2018	0.635
2019	0.369
2020	-0.290
2021	2.784
2022	9.805
2023	1.891
2024	2.064
2025	1.936
2026	2.017
2027	1.983
2028	1.984
2029	1.985