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Figure 1 Kaplan-Meier curves of myocardial infarction-free survival at six months for the three income groups. The p values are: p < 0.01 by the log-rank test for comparison between the high-income and low-income groups; p = 0.08 by the log-rank test for comparison between the middle-income and low-income groups; p = 0.10 for comparison between the high-income and middle-income groups.