You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Economic_inequality

Context:
According to International Monetary Fund economists, inequality in wealth and income is negatively correlated with the duration of economic growth spells (not the rate of growth). High levels of inequality prevent not just economic prosperity, but also the quality of a country's institutions and high levels of education. According to IMF staff economists, "if the income share of the top 20 percent (the rich) increases, then GDP growth actually declines over the medium term, suggesting that the benefits do not trickle down. In contrast, an increase in the income share of the bottom 20 percent (the poor) is associated with higher GDP growth. The poor and the middle class matter the most for growth via a number of interrelated economic, social, and political channels."

Question:
Who matters the most for economic growth?

The poor and the middle class