Exams in 2nd ESO

One of the questions in the exam was to EXPLAIN something:

Explain how did the crisis affect the demographics of the different kingdoms, which kingdom was most affected (6 points)

POPULATION OF THE PENINSULAR KINGDOMS (x 1000)
	1300	1480
Crown of Castile	4 500	4500
Catalonia	450	260
Valencia	200	250
Balearics	50	80
Aragon	200	250