UK uses/used brake horse power which is the same as SAE gross horsepower that USA uses/used.
the rest of the world uses/used PS (HP) which is metric horsepower and 98.6% of brake horsepower. british horse power is just a very old fashioned name for brake horse power.
The reason they all advertised the PS value is due to it being 98.6% of bhp, therefore if a car has 98.6bhp it can be advertised as 100HP so it looks better.
Some places use KW like south africa i know do off the top of my head. KW specification is indiscriminate and would be a better measurement for everyone to use.
The reason i say uses/used is because the SAE created a certified power measurement in '05 that is much more controlled and gives much more realistic and consistent results. Some manufacturers adopted this new system and some havent, the reason being it is not a higher or lower measurement as a trend, some engines produce bigger numbers under this system and some produce smaller. Obviously manufacturers dont want to advertise a smaller number as their headline figure