Year	mm Hg
1980	123.9
1981	123.9
1982	123.9
1983	123.8
1984	123.7
1985	123.6
1986	123.6
1987	123.6
1988	123.6
1989	123.7
1990	123.9
1991	124
1992	124.2
1993	124.4
1994	124.5
1995	124.7
1996	124.8
1997	124.9
1998	125
1999	125.1
2000	125.1
2001	125.1
2002	125.1
2003	125.2
2004	125.3
2005	125.4
2006	125.5
2007	125.6
2008	125.7