The Paris MoU port state control organisation has revealed Sweden to be the best-performing flag for 2015.
This is based on inspections and detentions over a three-year rolling period for registers with at least 30 vessel checks during that time.
The white list of quality registers remained unchanged with 43 flags, as did the grey list of average performers with 19.
The black list added one flag to reach 11.
Portugal and Spain won promotion to the white list, with Sweden coming out on top.
The next best were the UK, France, Denmark and Norway.
India and Switzerland have fallen to grey from white, while Saint Kitts and Nevis has been moved from grey to black.
The poorest performing flags were Tanzania, Moldova, Togo, Comoros and Cook Islands.
Paris MoU said that among the best performing classification societies were DNV GL, ABS, Lloyd’s Register (LR) and Korean Register of Shipping (KRS).
Those at the bottom included International Register of Shipping (IS), Universal Shipping Bureau Inc (USB) and Bulgarian Register of Shipping (BRS).