The aggregate demand curve shows the relationship between the aggregate price level and the quantity of aggregate output demanded. The curve is downward sloping due to the wealth effect of a change in the aggregate price level and the interest rate effect of a change in the aggregate price level. Corresponding to the actual 1933 data, here the total quantity of goods and services demanded at an aggregate price level of 7.3 is $778 billion in 2009 dollars. According to our hypothetical curve, however, if the aggregate price level had been only 4.2, the quantity of aggregate output demanded would have risen to $1,000 billion.