They haven't. The quote I gave is the total displaced population, "... of which 6.6 million are internally displaced within Syria, and over 4.8 million are refu

They haven't. The quote I gave is the total displaced population, "... of which 6.6 million are internally displaced within Syria, and over 4.8 million are refugees outside of Syria." Only 5 million/18 million = 28% of the population has left the country.