Here's an interesting piece by BBC News about the number of British Citizens living overseas. You can hunt around for your own country to see how many infiltrators are amongst you >8^D
The figures for Thailand are given as:
Total: 41,000 Inc. part-time: 51,000 Pensioners: 1,163
For some reason the gender breakdown (%male/female) are not given ('n/a')... perhaps they broke the '9' on their keyboard when typing the male figure 99.9999999999999999999999999999999999999999999999999999999999999...% 8^)
Any other countries have this data for their citizens?