Year	mmol per litre
1980	4.748
1981	4.761
1982	4.774
1983	4.785
1984	4.797
1985	4.812
1986	4.83
1987	4.846
1988	4.859
1989	4.873
1990	4.881
1991	4.893
1992	4.902
1993	4.912
1994	4.922
1995	4.934
1996	4.944
1997	4.955
1998	4.971
1999	4.985
2000	4.999
2001	5.013
2002	5.029
2003	5.042
2004	5.053
2005	5.062
2006	5.071
2007	5.078
2008	5.084