pre_text: Share-based Compensation Expense The following table summarizes total compensation costs recognized for share-based payments during the years ended December 31, 2019, 2018 and 2017: Income tax benefits related to share-based compensation of approximately $1.8 million, $1.3 million and $1.1 million were recorded for the years ended December 31, 2019, 2018 and 2017, respectively. Share-based compensation expense is included in “selling, general and administrative expenses” in the accompanying consolidated statements of operations. As of December 31, 2019, total unrecognized compensation cost related to non-vested RSAs and PSAs was $10.6 million and will be recognized over a weighted-average period of approximately 1.7 years.
table: Year Ended December 31,
table: (In thousands) 2019 2018 2017
table: Restricted stock $ 4,013 $ 3,249 $ 1,986
table: Performance shares 2,823 1,870 780
table: Total $ 6,836 $ 5,119 $ 2,766
question: Analyse this data from a financial earnings document. What was the average performance shares for 2017-2019?