Year	Percent change (Units)
1980	22.037
1981	3.193
1982	2.425
1983	-1.184
1984	1.645
1985	-1.302
1986	2.620
1987	1.928
1988	1.108
1989	3.134
1990	4.559
1991	3.891
1992	3.415
1993	4.625
1994	2.655
1995	4.564
1996	2.526
1997	0.265
1998	2.117
1999	0.148
2000	1.639
2001	-1.685
2002	0.777
2003	-0.061
2004	1.616
2005	2.205
2006	0.684
2007	3.325
2008	1.269
2009	-0.246
2010	1.234
2011	2.027
2012	1.618
2013	0.331
2014	0.607
2015	0.127
2016	1.692
2017	1.216
2018	-0.062
2019	1.151
2020	0.041
2021	2.631
2022	2.712
2023	2.698
2024	2.187
2025	1.718
2026	1.533
2027	1.514
2028	1.552
2029	1.539