Only from curiosity: what part of the world are you living in?
Mains voltage has been changed during the 1990ies (and earlier) from 220 or 240 to 230 Volts in many parts of the world. 
Of course there are some countries left that use 220 Volts like China, Greenland, Argentina and several countries of Africa. But whole Europe, Australia, Russia, India and many others use 230 Volts now.
And of course North Amercia is using 120 Volts still.
World Map of Mains Voltages and Frequencies
Edit: Most part of Australia is still 240 V (thank you Paul__B). So the map (link did not work - sorry - but now fixed) may not be right with this area.