etworks. The lowest densities are typical in Latin America, Africa, and India. When we combine the spectrum resources and site densities together, we can conclude that there are likely challenges with network capacity in the United States, India, and in many developing countries in Asia and in Africa. Mobile Data Traffic Growth 8.4.1 Mobile Data Volume Early technology visions for the year 2020 indicated that the expected mobile traffic may be very high - even 1 GB/person/day. Such high mobile data traffic was considered a very bold target 10 years ago, but the growth was even higher in many networks. Mobile data traffic exceeded 1 GB/person/day in some countries already in 2018 and will exceed it in many countries by 2020. Figure 8.5 shows the mobile data usage per person per day 8.4 Mobile Data Traffic Growth Mobile data usage per person per day in Finland 10.000 1.000 GB 0.100 0.010 0.001 Figure 8.5 Mobile data usage per person per day in Finland. in Finland from 2008 until 2018. The usage exceeded 1 GB per day during 2018. The total growth in 10 years has been 300x, corresponding to a nearly 80% annual growth rate on average. Mobile data usage is nearly as high in Taiwan and Saudi Arabia as well. The very high data usage requires two conditions: first, the networks need to have good quality in terms of coverage and capacity, and second, the data pricing needs to be flat rate. When these conditions are fulfilled, the customers tend to use lot of LTE mobile data because it is SO convenient. The total global mobile data during 2018 was approximately 600 petabytes (PB) day, that is 600 000 terabytes (TB) or 600 000 000 gigabytes (GB). Most of that data consumption is created in China, India, the United States, and Europe. Figure 8.6 illus- trates the estimated total mobile data usage per day in those four leading regions. The United States was the leading market in terms of mobile data until 2016, while all four areas had roughly similar data volumes during 2017. The fast growth in China and India made those coun