Table 2.

 Thirty-day Patient-level AMI Mortality from 2002 to 2008

Year	Population treated	Mean mortality	Standard deviation
2002	64933	0.1563	0.3631
2003	64776	0.1506	0.3576
2004	66226	0.1415	0.3485
2005	62433	0.1396	0.3465
2006	59760	0.1309	0.3373
2007	59017	0.1247	0.3304
2008	56180	0.1196	0.3245
2002–8	433,325	0.1381	0.3451

Observations are limited to patients between 39 and 100 years of age with a length of stay greater than two days, treated at sites that treated more than 99 AMIs per year. Unlike the regressions that we present, we do not limit the distance that patients travelled for care. AMI, acute myocardial infarction.