The graph below shows the education level of youths over the past $100$100 years.
Which of the following statements below describe how the education level has changed over this period of time.
The education level has increased at a decreasing rate over the past $100$100 years.
The education level has decreased at a decreasing rate over the past $100$100 years.
The education level has increased at an increasing rate over the past $100$100 years.
The education level has decreased at an increasing rate over the past $100$100 years.