what was average income tax benefit realized for the three year period?
Important information:
text_0: the following table provides the weighted average assumptions used in the black-scholes option-pricing model for grants and the resulting weighted average grant date fair value per share of stock options granted for the years ended december 31: .
table_1: the intrinsic value of 2018 is $ 9 ; the intrinsic value of 2017 is $ 10 ; the intrinsic value of 2016 is $ 18 ;
table_3: the income tax benefit realized of 2018 is 2 ; the income tax benefit realized of 2017 is 3 ; the income tax benefit realized of 2016 is 6 ;
Reasoning Steps:
Step: average2-1(income tax benefit realized, none) = 3.67
Program:
table_average(income tax benefit realized, none)
Program (Nested):
table_average(income tax benefit realized, none)

Please answer the following financial question based on the context provided. Make sure to give the answer in raw number, not in percentage and without any units. If the question asks for percentage the value should be less than 1
Context:
the following table provides the weighted average assumptions used in the black-scholes option-pricing model for grants and the resulting weighted average grant date fair value per share of stock options granted for the years ended december 31: .
Table
                            | 2018 | 2017 | 2016
intrinsic value             | $ 9  | $ 10 | $ 18
exercise proceeds           | 7    | 11   | 15  
income tax benefit realized | 2    | 3    | 6   
stock units during 2018 , 2017 and 2016 , the company granted rsus to certain employees under the 2007 plan and 2017 omnibus plan , as applicable . rsus generally vest based on continued employment with the company over periods ranging from one to three years. .
Question: 
what was average income tax benefit realized for the three year period?
Important information:
text_0: the following table provides the weighted average assumptions used in the black-scholes option-pricing model for grants and the resulting weighted average grant date fair value per share of stock options granted for the years ended december 31: .
table_1: the intrinsic value of 2018 is $ 9 ; the intrinsic value of 2017 is $ 10 ; the intrinsic value of 2016 is $ 18 ;
table_3: the income tax benefit realized of 2018 is 2 ; the income tax benefit realized of 2017 is 3 ; the income tax benefit realized of 2016 is 6 ;
Reasoning Steps:
Step: average2-1(income tax benefit realized, none) = 3.67
Program:
table_average(income tax benefit realized, none)
Program (Nested):
table_average(income tax benefit realized, none)
