Source: Technology Review
The ITU claims that 90 percent of the world's population is already covered by 2G networks, many of which can provide data services like Internet access via slower "2.5G" technologies such as EDGE and GPRS. The more modern 3G networks that have catalyzed the current smart-phone boom by providing richer, quicker mobile experiences have been expanding rapidly and now cover 45 percent of the world's population, more than three billion people.