Allocation of Stock-Based Compensation by Functional Category

The following table details the amount of stock-based compensation that is allocated to functional expense categories for each of the years in the three-year period ended December 31, 2022 (in thousands):


	2022		2021		2020
Direct operating expense	$	1,459	$	1,310	$	1,078
Brokered natural gas and marketing expense		2,439		1,794		1,416
Exploration expense		1,578		1,507		1,279
General and administrative expense		42,023		39,673		32,905
Exit costs		—		—		2,165
Total stock-based compensation	$	47,499	$	44,284	$	38,843

Schedule of Share Based Payment Award Performance Stock Awards Valuation Assumptions

The following assumptions were used to estimate the fair value of the TSR awards granted during the years ended December 31, 2022, 2021 and 2020:


	Year Ended December 31,
	2022			2021			2020
Risk-free interest rate		1.4	%		0.2	%		1.4	%
Expected annual volatility		68	%		75	%		65	%
Grant date fair value per unit	$	27.90		$	12.58		$	3.85

Summary of Non-Vested Awards Activities

The following is a summary of our non-vested internal performance metric awards activities at December 31, 2022:


	Number of Units			Weighted Average Grant Date Fair Value
Outstanding at December 31, 2021		1,095,355		$	7.80
Units granted (a)		153,089			20.38
Vested (b)		(243,482	)		9.64
Forfeited		—			—
Outstanding at December 31, 2022		1,004,962		$	9.27

(a) Amounts granted reflect the number of performance units granted; however, the actual payout of shares may be between zero and 200%

depending on achievement of specifically identified performance targets.

(b) For awards granted in 2019, the aggregate payout was approximately 116% of target with a positive performance adjustment of 158,793

shares.

Summary of Non-Vested Awards Activities

The following is a summary of our non-vested TSR award activities:


	Number of Units			Weighted Average Grant Date Fair Value
Outstanding at December 31, 2021		1,147,994		$	7.60
Granted (a)		111,828			27.90
Vested and issued (b)		(314,152	)		11.34
Forfeited		—			—
Outstanding at December 31, 2022		945,670		$	8.76

(a) These amounts reflect the number of performance units granted. The actual payout of shares may be between zero and 200% of the

performance units granted depending on the total shareholder return ranking compared to our peer companies at the vesting date.

(b) Includes TSR awards issued related to the 2019 performance period where the return on our common stock was 127% and therefore, the

performances multiple and actual payout was 183%.