The site http://kropla.com/electric.htm describes the electricity supply around the world. How accurate is it?

I have stumbled across this site the other day. It seems to describe the electricity supply for a lot of countries around the world. It also describes the type of electric sockets used around the world.The site seems useful for travellers when trying to determine what adaptors and converters they need to take. I would also like to use it as a source of info if it contains reliable and accurate information.

It seems accurate for the handful of countries I have visited but there are a lot of countries I haven't visited. Does this site contain accurate information for the countries you have been to?