The growth in the number (in millions) of Internet users in the United States between 1990 and 2015 can be approximated by a logistic function with k = 0.0018, where t is the number of years since 1990. In 1990 (when t = 0), the number of users was about 2 million, and the number is expected to level out around 250 million.
a. Find the growth function G(t) for the number of Internet users in the United States. Estimate the number of Internet users in the United States and the rate of growth for the following years.

b. 1995

c. 2000

d. 2010

e. What happens to the rate of growth over time?