Year	Percent change (Units)
1991	-4.795
1992	-4.214
1993	0.429
1994	32.051
1995	9.142
1996	2.782
1997	0.950
1998	3.066
1999	-1.416
2000	2.586
2001	5.182
2002	4.128
2003	-4.987
2004	1.480
2005	3.316
2006	3.594
2007	2.354
2008	8.051
2009	1.479
2010	1.833
2011	5.259
2012	2.400
2013	0.000
2014	1.147
2015	0.965
2016	-0.758
2017	1.747
2018	0.780
2019	-3.320
2020	0.721
2021	8.847
2022	7.763
2023	-0.580
2024	0.700
2025	2.000
2026	2.000
2027	2.000
2028	2.000
2029	2.000