Finland and Australia lead the world with 99% 4 Mbps adoption rates.
According to the Akamai Q4 2015 State on the Internet report, Australia and Finland led the world with the 4 Mbps broadband adoption rates for mobile connectivity, with both nations recording 99% adoption.
Australia also recorded the highest global average peak mobile connection speeds with 153.3 Mbps.
Four other countries joined Australia in the top five with recorded average peak speeds above 100 Mbps: Japan, Israel, Thailand, and the United Arab Emirates.
Looking at the actual report, the following figures were quoted:
The 2015 Q4, Global Average Peak Connection Speed is 32.5 Mb/s
The Top Ten Global Average Peak Connection Speeds were:
Singapore average Peak Connection Speed is 135.7 Mb/s
Hong Kong average Peak Connection Speed is 105.2 Mb/s
South Korea average Peak Connection Speed is 95.3 Mb/s
Macau average Peak Connection Speed is 83.1 Mb/s
Japan average Peak Connection Speed is 82.9 Mb/s
Indonesia average Peak Connection Speed is 79.8 Mb/s
Mongolia average Peak Connection Speed is 78.9 Mb/s
Taiwan average Peak Connection Speed is 78.8 Mb/s
Qatar average Peak Connection Speed is 77.8 Mb/s
Romania average Peak Connection Speed is 73.6 Mb/s
These figures, I will assume, were for landline broadband, and not comparable to the Mobile rate shown above for Australia.