Year	mm Hg
1980	125.7
1981	125.7
1982	125.6
1983	125.6
1984	125.7
1985	125.7
1986	125.7
1987	125.8
1988	125.8
1989	125.9
1990	125.9
1991	125.9
1992	125.8
1993	125.7
1994	125.7
1995	125.6
1996	125.4
1997	125.3
1998	125.2
1999	125.2
2000	125.1
2001	125.1
2002	125.1
2003	125.1
2004	125.1
2005	125.1
2006	125.2
2007	125.2
2008	125.3