The Steamspy site is only responsible for collecting information on sales of Steam. Each scale, they have published featuring interesting charts where the average sales price range seen by the store, along with a list of some of the games that belong. Interestingly, as this report demystifies the idea that the PC user only consumes deals at very low prices, because even though most of the games in the catalog are priced at $ 9.99 and $ 4.99, the highest consumption is in the range from $ 50 to $ 69.99.
Note that the chart does not speak of total sales (GTAV reached 2.4 million copies sold on its own), but the average of the total units of games with the same price.
The reality is that there are very many more games low price the scale found in Triple A, which can reduce the average enough when games are grouped with sales few successful games. Also, is it that, despite being the most expensive and repetitive, the public still prefers the big productions?