What Has Happened to the Proportion of the World's Population

What has happened to the proportion of the world's population living in abject poverty?

A) The proportion of the world's population living in abject poverty has declined since the 1980s.
B) Economic growth has increased so much that almost none of the world's population lives in abject poverty.
C) The proportion of the world's population living in abject poverty has increased slightly.
D) The proportion of the world's population living in abject poverty has stayed the same.