Year	mmol per litre
1980	6.036
1981	6.012
1982	5.983
1983	5.954
1984	5.927
1985	5.901
1986	5.875
1987	5.85
1988	5.827
1989	5.804
1990	5.778
1991	5.755
1992	5.733
1993	5.708
1994	5.685
1995	5.661
1996	5.638
1997	5.616
1998	5.595
1999	5.575
2000	5.553
2001	5.532
2002	5.509
2003	5.487
2004	5.462
2005	5.435
2006	5.407
2007	5.384
2008	5.36