Answer: 60 million per year
Explanation:
The average rate of change in the number of public library visits from 1994 to 1999 will be calculated thus:
Average rate of change = change in number of vists in billions / number of years passed
= (1.6 billion - 1.3 billion) / 1999 - 1994
= 0.3 billion/5
= 60,000,000
= 60 million per year