The provided chart illustrates the share of the world's population living in extreme poverty from 1820 to 2018. As shown, this share remained very high for the first century of this period and then began a steep decline, particularly in the latter half of the 20th century. Based on your general knowledge of economic and social history, propose and justify two major historical developments or forces you believe were most responsible for this dramatic reduction in extreme poverty. For each factor, explain how it contributed to this outcome.