What country has the highest rate of left handed people?
This is a complicated question to answer because it is tied to the history of handedness. It is estimated that 10% of the world's population is left-handed but in certain areas of the world the percentage is higher and in other areas lower. This is related to the sad fact that throughout history there was a great deal of bias and stigma associated with being left-handed and lefties were forced to use their right hands. This bias still exists in many cultures today. Only in recent years North America and Western Europe have taken a more liberal stance on handedness and permitted children to use their naturally dominant hand. The rates of lefties in these countries tend to be higher, approximately 12%. In Asian, Muslim and Latin American counties the rates tend to be lower. In countries where children are still forced to stop using their dominant left hand such as Korea (2%), Japan (3%) and Taiwan (5%) you will find the lowest percentage of lefties. Most of these statistics can be found at Handedness Statistics.
Because it wasn't until recent times that many countries stopped this practice, older generations will report less lefties since those were the generations forced to use their right-hands. Even in the twentieth century the Soviet bloc countries persisted in discouraging left-handedness. It is hard to believe but in Albania it was actually made a crime to be left-handed (History of Handedness - Recent History).
Therefore, the countries that have a longer history of permissiveness in allowing the natural use of the left-hand will show the largest percentage of lefties, while the countries that have a shorter permissive history will have a lower percentage of lefties. It will only be sometime in the future when all lefties are allowed to use their dominant hands that we will be able to get a more accurate idea of how many lefties there really are.