The population of Western Asia was estimated at 272 million as of 2008, projected to reach 370 million by 2030 by Maddison . This corresponds to an annual growth rate of 1.4% , well above the world average of 0.9% .The population of Western Asia is estimated at about 4% of world population, up from about 39 million at the beginning of the 20th century, or about 2% of world population at the time. The most populous countries in the region are Turkey and Iran and, each with around 79 million people, followed by Iraq and Saudi Arabia with around 33 million people each. Numerically, Western Asia is predominantly Arab, Persian, Turkish, and the dominating languages are correspondingly Arabic, Persian and Turkish, each with of the order of 70 million speakers, followed by smaller communities of Kurdish, Azerbaijani, Hebrew, Armenian and Eastern Aramaic. The dominance of Arabic and Turkish is the result of the medieval Arab and Turkic invasions beginning with the Islamic conquests of the 7th century AD, which displaced the formerly dominant Aramaic and Hebrew in the Levant, and Greek in Anatolia, although Hebrew is once again the dominant language in Israel, and Aramaic  and Greek both remain present in their respective territories as minority languages. Other significant native minorities include Assyrians, Druze, Jews, Mandeans, Maronites, Shabaks, Syriac Arameans, Lurs and Yezidis.
Which is less populated, Iraq and Saudi Arabia or Turkey and Iran?
Iraq and Saudi Arabia