I do notice something! Each percentage represents the percentage of countries that are in a particular continent, correct to 1 decimal place. For example, Africa has 54 countries, and 54/196 is approximately 27.6%. The missing percentage is 11.7%, representing the percentage of countries in North America. (And, unless I misinterpreted something, the final percentage in the challenge should be 6.1% rather than 6.5%.)
'mushroomsteve'........ you have done it again. Congratulations....... As you say the numbers given are the %of Countries in each continent (of the 196 Countries of Jetpunk) Africa 27.6% / Asia 24.5% / Europe 23% / Oceania 7.1% / S. America 6.1% and that only leaves N. America at 11.7% as you suggested. Honorary Gold Medal is on the way.... Congratulations........ PS 'mushroomsteve' has 8 CHALLENGE solves .Congratulations again!