What are the most popular sports in the world based on number of fans?

According to a 2010 survey the most popular sports in the world by fan count are:

#1--Football (soccer), approximately 3.5 billion fans.

#2--Cricket, approximately 2.5 billion fans.

#3--Field hockey, approximately 2 billion fans.

#4--Tennis, approximately 1 billion fans.

The other six completing the top ten are:

volleyball, table tennis, baseball, golf, American football and basketball.