5 Year Impact Factor for the Journal of Economic Growth

Following yesterday's post on the 2 year impact factor for the Journal of Economic Growth I tried to compute the 5 year factor. According to Journal Citation Reports it's 3.467 but I came up with 3.283 with a standard deviation of 0.52. It's not unusual apparently to not be able to reproduce the exact impact factors published in the JCR. Anyway, the 95% confidence interval is from 2.25 to 4.32.