- Regular definitive stamps overprinted Official were introduced on 2
July 1981, and all government offices and the Philatelic Bureau began
using them on outgoing mail. The use of TO-1 was slowly phased out.
- TO-1 is known used to cancel stamps on commercial mail, probably done
- TO-2 does not appear to have been put into regular use, as the
Philatelic Bureau has always used postage stamps on all outgoing mail. It
is very rare, known on piece dated 1 Jan 1976. Examples are known from
1983 used by favour on covers, without the date plugs, and having the date
written in by hand.