Year	mm Hg
1980	127
1981	126.8
1982	126.7
1983	126.6
1984	126.5
1985	126.4
1986	126.2
1987	126.1
1988	126
1989	125.9
1990	125.8
1991	125.7
1992	125.6
1993	125.5
1994	125.5
1995	125.4
1996	125.3
1997	125.2
1998	125.1
1999	125
2000	124.9
2001	124.9
2002	124.9
2003	124.9
2004	125
2005	125.1
2006	125.2
2007	125.3
2008	125.4