Year	Percent change (Units)
1980	18.803
1981	7.886
1982	7.466
1983	4.414
1984	17.379
1985	13.801
1986	8.596
1987	8.866
1988	8.722
1989	9.292
1990	-4.049
1991	6.896
1992	6.467
1993	5.417
1994	7.505
1995	7.377
1996	9.084
1997	12.628
1998	9.777
1999	7.232
2000	4.737
2001	1.450
2002	6.098
2003	14.153
2004	6.031
2005	-11.223
2006	23.606
2007	7.123
2008	8.980
2009	-8.158
2010	6.835
2011	8.573
2012	2.364
2013	6.963
2014	7.801
2015	3.972
2016	6.572
2017	7.055
2018	8.668
2019	7.298
2020	-32.909
2021	37.687
2022	13.907
2023	4.424
2024	5.170
2025	6.504
2026	5.000
2027	4.800
2028	4.499
2029	4.499