African internet usage has grown by a staggering 882 % over the past 7 years, second only to the Middle East.  However the percentage of the population with an internet connection is still the lowest globally at 4.7%. [the table does not explain whether the % refers to numbers having internet at home or those having access to the internet.] 
The top ten internet countries is somewhat misleading as the figures do not represent the actual percentage of users.  For example Nigeria is listed first yet this only reflects 5.9% of the population or 8 million out of 135 million people. Still an enormous growth from 2000 when there were only 200,000 users. Compare this with Kenya listed as 6th but with 7.5% of the population have internet and South Africa listed as 4th but with 11.6% of the population.  NOTE for SA this translates into a mere 1.8% of the Black population compared to 97% of white South Africans. 
If anyone is overly interested in internet usage statistics there is a dedicated blog called  "a-stat-a-day" which provides a huge selection of data presented with graphs and lots of colourful maps etc.