Year	Percent change (Units)
1980	2.692
1981	11.610
1982	5.817
1983	-0.925
1984	-0.443
1985	-0.236
1986	2.031
1987	0.416
1988	0.946
1989	0.866
1990	2.975
1991	2.552
1992	1.845
1993	4.031
1994	4.128
1995	3.973
1996	1.964
1997	3.919
1998	3.673
1999	2.294
2000	3.030
2001	2.518
2002	2.626
2003	1.939
2004	2.719
2005	2.529
2006	2.570
2007	0.713
2008	4.676
2009	1.836
2010	2.032
2011	2.516
2012	3.225
2013	0.991
2014	0.777
2015	1.168
2016	0.897
2017	1.262
2018	1.735
2019	1.519
2020	0.794
2021	0.715
2022	6.125
2023	5.655
2024	2.861
2025	2.115
2026	2.026
2027	1.998
2028	1.998
2029	2.000