Year	kt
1990	218.2
1991	221.4
1992	218.5
1993	222
1994	225.2
1995	235.2
1996	254.8
1997	267.6
1998	286
1999	299.3
2000	312.5
2001	321.9
2002	335.1
2003	360.7
2004	367.4
2005	376.7
2006	398
2007	419.2
2008	428.1
2009	453.6
2010	465.8
2011	456.1
2012	469.9
2013	472.9
2014	476.6
2015	490.2
2016	500.5
2017	500.1
2018	508.6
2019	509
2020	474.6