Year	Percent change (Units)
1980	11.200
1981	24.015
1982	19.600
1983	8.798
1984	-1.721
1985	-4.942
1986	15.455
1987	25.927
1988	10.942
1989	11.478
1990	14.358
1991	10.174
1992	15.699
1993	14.583
1994	14.729
1995	11.750
1996	10.207
1997	27.184
1998	14.383
1999	6.683
2000	5.077
2001	13.495
2002	-3.458
2003	5.564
2004	7.336
2005	10.930
2006	18.005
2007	11.546
2008	11.774
2009	10.406
2010	5.375
2011	28.799
2012	3.469
2013	13.487
2014	12.431
2015	5.816
2016	15.410
2017	1.740
2018	6.315
2019	13.964
2020	-14.214
2021	7.150
2022	21.207
2023	4.950
2024	3.929
2025	7.753
2026	8.160
2027	8.830
2028	10.122
2029	12.129