Android (operating system) store, and by September 2013, one billion Android devices have been activated. , the Google Play store has over 2.7 million Android applications published, and , apps have been downloaded more than 65 billion times. The operating system's success has made it a target for patent litigation as part of the so-called "smartphone wars" between technology companies. Android devices account for more than half of smartphone sales in most markets, including the US, while "only in Japan was Apple on top" (September–November 2013 numbers). At the end of 2013, over 1.5 billion Android smartphones have been sold in the four
Market share adjustments. Firms with market shares below a certain level may not be viable. Similarly, within a firm’s product line, market share trends for individual products are considered early indicators of future opportunities or problems." Research has also shown that market share is a desired asset among competing firms. Experts, however, discourage making market share an objective and criterion upon which to base economic policies. The aforementioned usage of market share as a basis for gauging the performance of competing firms has fostered a system in which firms make decisions with regard to their operation with careful consideration of the impact