Measuring metric adoption by counting countries with official adoption is common. Less common is measuring by aggregate PPP-GDP and actual adoption by the publi

Measuring metric adoption by counting countries with official adoption is common. Less common is measuring by aggregate PPP-GDP and actual adoption by the public. To approximate actual adoption, I give the US, UK, Canada and Jamaica completely to traditional units and the rest of the world completely to metric.* Using 2011 data from the IMF, I then conclude that traditional units command 31% of usage worldwide. * These are the countries in red on this table http://en.wikipedia.org/wiki/Metrication#Chronology_and_status_of_conversion_by_country http://en.wikipedia.org/wiki/Metrication#Chronology_and_stat... But a review of the UK article shows that the language "partially complete" is pretty fanciful in describing the current situation in the UK. The story in China is more complex...