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
Relative market share share of 25% would be a powerful leader in many markets but a distant “number two” in others. Relative market share offers a way to benchmark a firm’s or a brand’s share against that of its largest competitor, enabling managers to compare relative market positions across different product markets. Relative market share gains some of its significance from studies–albeit controversial ones—suggesting that major players in a market tend to be more profitable than their competitors. Relative market share can also be calculated by dividing brand sales by largest competitor sales because the common factor of total market sales (or revenue)