Usage share of operating systems computer's installed base statistics, and actual (web) use needs not follow installed base. Also, Microsoft includes tablets (but StatCounter may also for Windows, while it wouldn't for e.g. Android). Video game store Steam publishes a monthly "Hardware & Software Survey", with the statistics below: By Q1 2018, mobile operating systems that can be found on smartphones, include Google's dominant Android (and variants) and Apple's iOS, with both combined at almost 100% market share. According to research by InsightPortal, there is a clear correlation between the GDP per capita of a country and that country's respective smartphone OS market share, Showing
Market share to help the brand identify market share growth opportunities. "Although market share is likely the single most important marketing metric, there is no generally acknowledged best method for calculating it. This is unfortunate, as different methods may yield not only different computations of market share at a given moment, but also widely divergent trends over time. The reasons for these disparities include variations in the lenses through which share is viewed (units versus dollars), where in the channel the measurements are taken (shipments from manufacturers versus consumer purchases), market definition (scope of the competitive universe), and measurement error." Market share