Different standards use different abbreviations. Here, Tom is using FIPS: see http://en.wikipedia.org/wiki/List_of_FIPS_country_codes http://en.wikipedia.org/w

Different standards use different abbreviations. Here, Tom is using FIPS: see http://en.wikipedia.org/wiki/List_of_FIPS_country_codes http://en.wikipedia.org/wiki/List_of_FIPS_country_codes. If it were my site, I'd probably also use AU (and AT), though.