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2. Number of apps available in leading app stores as of 4th quarter 2020. https://www.statista.com/statistics/276623/number-of-apps-available-in-leading-app-stores/.
3. Mobile app usage-statistics and facts. https://www.statista.com/topics/1002/mobile-app-usage/.
4. Number of mobile app downloads worldwide from 2016 to 2020. https://www.statista.com/statistics/271644/worldwide-free-and-paid-mobile-app-store-downloads/.
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