Year	Percent change (Units)
1991	-2.300
1992	-7.100
1993	12.400
1994	-19.000
1995	10.348
1996	-0.085
1997	-12.203
1998	-6.115
1999	6.176
2000	-1.766
2001	-3.574
2002	-9.274
2003	-11.134
2004	17.342
2005	9.213
2006	36.270
2007	0.474
2008	2.532
2009	-7.536
2010	14.015
2011	3.356
2012	10.125
2013	-3.939
2014	-0.949
2015	2.006
2016	-2.576
2017	19.028
2018	-0.194
2019	12.045
2020	1.867
2021	-9.656
2022	15.516
2023	9.369
2024	4.047
2025	3.276
2026	0.868
2027	2.150
2028	0.657
2029	-14.174
