59. Small business. The percentage of the US. national income generated by nonfarm proprietors between 1970 and 2000 can be modeled by the function I given by 13.1:3 24ml mm + 585,000 75,000 where x is the number of years since 1970. (Source: Based on data from www.bls-gov.) Sketch the graph of this function for O E x E 40. Pix) = v