Year	mm Hg
1980	123.3
1981	123.4
1982	123.6
1983	123.8
1984	123.9
1985	124.1
1986	124.2
1987	124.4
1988	124.6
1989	124.7
1990	124.8
1991	125
1992	125.1
1993	125.2
1994	125.4
1995	125.5
1996	125.6
1997	125.7
1998	125.8
1999	125.9
2000	126
2001	126.1
2002	126.2
2003	126.3
2004	126.3
2005	126.4
2006	126.4
2007	126.5
2008	126.5