Year	Percent change (Units)
1981	0.900
1982	-0.600
1983	4.800
1984	7.400
1985	5.600
1986	2.100
1987	4.500
1988	9.000
1989	7.635
1990	6.081
1991	5.521
1992	2.403
1993	4.307
1994	9.692
1995	10.993
1996	3.285
1997	8.849
1998	7.061
1999	8.642
2000	14.199
2001	0.819
2002	0.556
2003	2.535
2004	10.081
2005	6.045
2006	8.173
2007	5.119
2008	0.627
2009	-10.134
2010	11.111
2011	5.028
2012	3.109
2013	1.876
2014	3.053
2015	5.074
2016	4.379
2017	6.009
2018	3.117
2019	1.306
2020	-2.122
2021	10.399
2022	2.261
2023	-1.568
2024	0.200
2025	2.200
2026	3.500
2027	3.500
2028	3.300
2029	3.300