Fix Sint Maarten (Dutch part) numeric country code

`Sint Maarten (Dutch part) ` was mistakenly assigned same as Singapore.

The correct numeric code is following.
- Singapore: 702
- Sint Maarten (Dutch part) : 534

https://www.evernote.com/shard/s363/sh/2e05151b-e010-4f38-bee7-ae62cad6d553/bc11941fd2423a6a9fbaa72bccccd368