Year	Percent change (Units)
1980	12.138
1981	8.987
1982	4.556
1983	3.486
1984	4.589
1985	4.802
1986	6.818
1987	4.053
1988	5.063
1989	4.356
1990	7.036
1991	6.410
1992	3.505
1993	2.646
1994	1.443
1995	1.625
1996	0.999
1997	0.791
1998	1.472
1999	1.547
2000	1.095
2001	2.553
2002	1.892
2003	3.098
2004	1.654
2005	1.205
2006	2.433
2007	2.697
2008	4.187
2009	1.643
2010	1.669
2011	3.042
2012	0.655
2013	0.955
2014	0.202
2015	2.024
2016	0.967
2017	1.613
2018	1.963
2019	1.434
2020	1.163
2021	4.129
2022	5.475
2023	1.901
2024	2.425
2025	2.123
2026	1.931
2027	1.867
2028	1.997
2029	1.976