US GDP (billions $) is given below. Indicate the business cycle phases. USGDP(billions$) 13856 14478 14719 14419 14964 18624 In what year the economy reaches its peak? [Select] v In what year the economy reaches its trough? [Select] v After what year the economy experiences a contraction? [Select] v After what year the economy experiences an expansion? [Select] v