Though I try to check the caption of each Royal Gazette publication, somehow the announcement listing the population for each province as of December 31st 2013 nearly slipped through. Luckily I spotted it being added as a reference to the population data of the province articles on Thai Wikipedia, just one day after it was published in the Royal Gazette.
As of this announcement, the registered population grew from 64,456,695 one year ago to 64,785,909, and increase of 329,214 or 0.5%. Ranong has the biggest population decrease with 4.5%, the biggest gain with 2.3% was Phuket. As the publication is in Thai with only Thai numerals, I have made the data into a little spreadsheet embedded below, including the 2012 data for comparison. In case anyone prefers it in XML, its within my Tambon project now as well.
While writing this posting, this population data is not yet available on the DOPA website, but I expect it to show up soon at stat.bora.dopa.go.th. The full population data down to subdistrict level and including the municipalities will also show up soon I guess.
In January the new datatype number was added to Wikidata, and I have already added some population data points to a few entities manually to try it out, of course most notably for my favourite province Surat Thani. And since I am also currently working on transferring the census data into my XML structure, I now really have to start to program the automatic editing of this kind of data in the TambonBot.