Table:
0
A
B
C
D
1
Year Ended May 31,
2
2019
2018
2017
3
Expected life (in years)
4.6
4.7
4.8
4
risk-free interest rate
2.7%
2.0%
1.0%
5
Volatility
24%
22%
23%
6
Dividend yield
1.7%
1.5%
1.5%
7
Weighted-average fair value per share
$10.77
$9.34
$8.18

Questions and formulas:
Question: What was the average dividend yield for the 3 years from 2017 to 2019?
Formula: (B6+C6+D6)/3
Formula2: (B6+C6+D6)/3
Level: Calculation
Question: What was the average risk-free interest rate over the 3 year period from 2017 to 2019?
Formula: (B4+C4+D4)/3
Formula2: (B4+C4+D4)/3
Level: Calculation