[itafroma]

> It is interesting to see that the gaming circle has decreased considerably in size over the years from 1984 to 2013 and has almost disappeared now.

>What could be probable reasons for the same?

The circles for each year are generated off of the results from the three-question survey Apple is conducting on that page (click the "Tell us about your first Mac" button below the lede). The questions are:

1. Which Mac was yours? (which determines the year)

2. Where were you? (which ostensibly determines which localized site your responses will count towards)

3. How did you use your Mac?

So the size of the gaming circle in a particular year is determined merely by the number of people who filled out that survey, self-reported that they bought their first Mac in that year, and said they used that first Mac for gaming.