Afghanistan is 24% larger than Yemen.
Area: 652,230 km2 World Factbook
Population: 31,822,848 (July 2014) World Factbook
Afghanistan, officially the Islamic Republic of Afghanistan, is a landlocked country located in Central Asia and South Asia. It has a population of around 31 million people making it the 42nd most populous country. Wikipedia
Area: 527,968 km2 World Factbook
Population: 26,052,966 (July 2014) World Factbook
Yemen, officially known as the Republic of Yemen, is an Arab country in Western Asia, occupying the southwestern to southern end of the Arabian Peninsula. Yemen is the second largest country in the peninsula, occupying 527,970 km². The coastline stretches for about 2,000 km. Wikipedia