Similar to the statistics for the subdistrict creations, I now also coded the same for the districts. For the statistics below I have only used the announcements since 1950, there's a bit higher chance of missing announcements before. And at least two district creations are missing, as I still could not find two announcements dating from 1978.
There were a total of 385 announcements in the Royal Gazette, in which 14 district (Amphoe) and 398 minor districts (King Amphoe). Most of the time it was just one district per announcement, the maximum number of districts per announcement was seven.
The most common number of subdistricts in a newly created district is three (154 times), the mean value is a little bit higher with 3.46. The highest number was 11, which occured at the creation of Singhanakhon district in Songkhla province. In four cases the newly created district consisted of a single subdistrict.
Pathum Ratchawongsa, Amnat Charoen.
And finally, not much surprising, the province with most district creations is also the province which has most districts today, Nakhon Ratchasima. A total of 19 districts were added to this province since 1950.