Which Central African nation has had the most stable government since they gained their independence?

Gabon.

Explanation:

Gabon has gone into independence and was originally a French colony however with it's relatively small population of 1.5 million people and with plenty of natural resources has made it into a stable democratic government with a higher standard of living.

2018 means 2018 ce or common era

there have been other eras too including bce, which included way more years.