Driving on the left

Why do some countries drive on the right

and others on the left ?

About a quarter of the world drives on the left, and the countries that do are mostly old British colonies. This strange quirk perplexes the rest of the world; but there is a perfectly good reason...

Read the following link and guess about the reason of driving on the left in some countries:

http://users.pandora.be/worldstandards/driving%20on%20the%20left.htm

After reading the website, answer to the following quiz:

1. How many countries drive on the left?

2. How many countries drive on the right?