On January 1, 2018, the Company adopted ASC 606 using the modified retrospective method, applied to those contracts for which all performance obligations were not completed as of that date. Under the modified retrospective method, results for reporting periods beginning after January 1, 2018 are presented using the guidance of ASC 606, while prior period amounts were not adjusted and continue to be reported in accordance with the previous guidance provided in ASC Topic 605, Revenue Recognition.

The impact of the adoption of ASC 606 on revenue recognized during the years ended December 31, 2020 and December 31, 2019 is as follows:

	2020			2019			2018
Contract liabilities with customers at January 1,	$	9,623		$	7,477		$	6,950
Revenue recognized		(14,570	)		(16,352	)		(20,653	)
Revenue deferred		5,031			18,498			21,180
Contract liabilities with customers at December 31,	$	84		$	9,623		$	7,477

During the year ended December 31, 2020, the Company deferred $5.0 million of revenue, offset by the recognition of $14.6 million of revenue previously deferred as the performance obligations relating to the shipment of free products were satisfied. This resulted in a net increase in firearms sales for the year ended December 31, 2020 of $9.6 million and a deferred contract revenue liability at December 31, 2020 of $0.1 million. The deferred revenue balance is significantly reduced due to the absence of promotions in the fourth quarter of 2020. The Company estimates that revenue from this deferred contract liability will be recognized in the first quarter of 2021.

During the year ended December 31, 2019, the Company deferred $18.5 million of revenue, offset by the recognition of $16.4 million of revenue previously deferred as the performance obligations relating to the shipment of free products were satisfied. This resulted in a net decrease in firearms sales for the year ended December 31, 2019 of $2.1 million and a deferred contract revenue liability at December 31, 2019 of $9.6 million.

During the year ended December 31, 2018, the Company deferred $21.2 million of revenue, offset by the recognition of $20.7 million of revenue previously deferred as the performance obligations relating to the shipment of free products were satisfied. This resulted in a net decrease in firearms sales for the year ended December 31, 2018 of $0.5 million and a deferred contract revenue liability at December 31, 2018 of $7.4 million.