Why did the number of European immigrants increase from 1945 to the early 1970s?

After 1945, Europe lived and worked in peace and contentment, and the economy lacked war, so the population increased rapidly.

Europe has a population density of 70 people /km, ranking sixth in the world? It is the third most populous continent in the world, second only to Asia and Africa. More than 99% of the population belongs to European origin, which is relatively single. Europe is one of the most livable continents with high living standards, high environmental and human development indexes.

The urban population accounts for about 64% of the population of the whole continent, ranking third among all continents after Oceania and North America. However, the population showed negative growth, with the most densely distributed population in the west of Europe, with more than 200 people per square kilometer in the central Rhine Valley, the Paris Basin, eastern Belgium and the lower reaches of the Thames. Most residents in Europe are white (Europa).

Religion: Catholicism and Christianity.

Extended data

Since17th century, Europe has gradually become the world economic center. /kloc-the first industrial revolution broke out in Europe in the 0/8th century. Europe became the economic center of the world at that time.

But after the two world wars in the 20th century, Europe gradually declined. Europe has made great contributions to the course of human history. Everything in modern civilization was laid by Europeans.

The level of economic development in Europe ranks first in all continents, and industry, transportation, commerce and trade, finance and insurance play an important role in the world economy. It is also a world leader in many scientific and technological fields. This is inseparable from the fact that Europe is the birthplace of modern industry, and the great geographical discovery and foreign colonial plunder in15 ~16th century.