Short answers, pulled from the story.
Greek city-states began colonizing the Mediterranean and Black Sea coasts from around 800 BC. This dramatic expansion included areas from the western Mediterranean to Asia Minor and the Black Sea.
The population of the areas of Greek settlement from the western Mediterranean to Asia Minor and the Black Sea in the 4th century BC has been estimated at up to 10 million. Estimates for the Greek-speaking population on the coast and islands of the Aegean Sea during the 5th century BC vary from 800,000 to more than 3,000,000.
Phoenicians established colonies including Hippo Regius, Icosium, Hadrumetum, Utica, Lixus, Tingis, Oea Tripoli, Gades Cadiz, Leptis Magna, Sabratha, Pharos Island Alexandria, many Mediterranean islands Sis Palermo Motya and Soluntum on Sicily, Kitiya Kition Crete, the Balearic Islands, Karaly Cagliari Sardinia, Porto at the Douro River, Lisbon at the Tagus River, Arambys Mogador Island Essaouira Morocco.
Greek historian Diodorus Siculus estimated that 7,000,000 inhabitants resided in Egypt during his lifetime before its annexation by the Roman Empire. Of this, he states that 300,000 citizens lived within the city of Alexandria.
Historians have developed two radically different accounts resting on different interpretations of the figures of 4,036,000 recorded for the census carried out by Augustus in 28 BC. They also interpret 4,233,000 in 8 BC and 4,937,000 in 14 AD.