How many apps do you have on your phone? It’s a question that few could answer accurately. Today, it’s getting to the point that many have trouble answering a question about how many mobile devices they have in their household. According to Gartner, this trend is translating into big numbers and staggering dollar amounts.

Mobile app stores will see annual downloads reach 102 billion in 2013, up from 64 billion in 2012, according to Gartner, Inc. Total revenue in 2013 will reach $26 billion, up from $18 billion in 2012. Free apps will account for 91 percent of total downloads in 2013 (see Table 1). Gartner said that in-app purchases (IAPs) will account for 48 percent of app store revenue by 2017, up from 11 percent in 2012.