The scores of 50 nurses taking a state board exam were recorded. A frequency distribution of these scores is shown below. A graph has a horizontal axis labeled Nursing Board Test Score with values from 50 to 100 and a vertical axis labeled Number of Nurses with values from 0 to 20. The frequency polygon has 5 dots. The location of the dots are given in the following class intervals: 50–60: 5 60–70: 8 70–80: 15 80–90: 18 90–100: 4 What percent of the nurses had scores between 70 and 90? %