A few years ago one member of the Amaravati sangha (disciples of Ajahn Sumedho mainly) made such a statistic, which I read but don't have the details now. But the drop-out rate was pretty high, some after the first 2-3 years, then after 10 years, then after 16-18 years, and even later -- so that in the end, there are just a few survivors from each generation. And yes, it is mainly Anglo-Saxon men who ordain, with a few other nationalities mixed in, but only few South Europeans for some reason (too easy-going?). Education does not play such a big role, but there might be a somewhat greater percentage of degrees in the Western Sangha than typical population.
Bhikkhu GavesakoKiṃkusalagavesī anuttaraṃ santivarapadaṃ pariyesamāno... (MN 26)ajahnchah.org
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