Answer:
The period between 1340 and 1450 saw more deaths in Western Europe than in Eastern Europe.
The percentage of decline during this period was 31.97%.
Step-by-step explanation:
The period between 1340 and 1450 was the period when the plague devastated the European population. All European regions had big losses in population because of this disease, but Western Europe had it the worst. more then a third of the population of Western Europe died during this period, while in Eastern Europe for comparison, it was around one quarter of the population, which was still a lot. The total population of the continent decreased for 31.97%. This had very big negative impact on the economies and military power of the European countries, but also triggered a lot of social changes in the European societies.