An epidemic follows the curve 900 P = 1 + 20,000e-0.549t million people, where P is the number of people infected and t is in years. How fast is the epidemic growing after 10 years? (Round your answer to two significant digits.) HINT [See Example 5.] million people infected per year How fast is the epidemic growing after 20 years? (Round your answer to two significant digits.) million people infected per year How fast is the epidemic growing after 30 years? (Round your answer to two significant digits.) million people infected per year