I appreciate the work you put into this, but when I look at the data, I see a nonstationary (humped) time series, where I am not sure that 2.4 standard deviatio

I appreciate the work you put into this, but when I look at the data, I see a nonstationary (humped) time series, where I am not sure that 2.4 standard deviations above the mean is a reliable identifier of outliers. Furthermore, I think the data still supports janandonly's point (though not quite as starkly) even if we throw out the maximum. It would indeed be pedantic of me to now make an issue of the maximum not in general being an outlier, but at the time I wrote that, I was replying to a post in which the only justification given for considering 1968 to be an outlier was the fact that it was the maximum.