Fig. 2.

Survival of E1 and E2 infants without any major morbidity. Panel A shows the percent survival without major morbidity for E1 (solid line) and E2 (dashed line) infants over 19 years with the best fitting regression lines superimposed on the data for each group of infants. The slope for E1 = 0.90% /year, p < 0.001. The slope for E2 = 1.26% /year, p < 0.001. Panel B is a plot of the difference in percent survival without major morbidity (E1 minus E2) for each year and the best fitting regression line. The slope is –0.36% /year, p < 0.013.