On January 1, 2018, we adopted ASC Topic 606, “Revenue from Contracts with Customers” ("ASC Topic 606") using the modified retrospective method applied to those contracts which were not completed as of January 1, 2018. Results for reporting periods beginning after January 1, 2018 are presented under ASC Topic 606, while prior period amounts are not adjusted and continue to be reported in accordance with our historic accounting under ASC Topic 605, "Revenue Recognition" ("ASC Topic 605").

We recorded an increase to opening retained earnings of $0.8 million (net of tax of $0.3 million) as of January 1, 2018 due to the cumulative impact of adopting ASC Topic 606, with the impact primarily related to the recognition of bill and hold transactions that were deferred under ASC Topic 605. The impact to net sales as a result of applying ASC Topic 606 for the year ended December 31, 2018 was an increase of $0.2 million.

In accordance with the new revenue standard requirement, the disclosure impact of adoption on our consolidated statement of income for the year ended December 31, 2018 and the consolidated balance sheet as of December 31, 2018 was as follows:



	For the Year Ended December 31, 2018
	As Reported		Balance without Adoption		Effect of Change
Net sales	$	7,202.5	$	7,202.3	$	0.2
Cost of merchandise sold		5,821.6		5,821.6		—



	As of December 31, 2018
	As Reported		Balance without Adoption		Effect of Change
Merchandise inventory	$	658.7	$	668.2	$	(9.5)
Other current assets		54.1		54.4		(0.3)
Other non-current liabilities		8.7		19.4		(10.7)
Retained earnings		678.1		677.2		0.9

The following table summarizes the percentages of our net sales attributable to each of our vertical markets for the years ended December 31, 2019, 2018, and 2017:



	For the Years Ended December 31,
	2019		2018		2017
Construction	60.1	%	59.7	%	58.7	%
CIG	20.6		20.8		21.1
Industrial & Utility	19.3		19.5		20.2
Total net sales	100.0	%	100.0	%	100.0	%

Certain reclassifications have been made to the vertical market assigned to customers in the prior years’ information to conform to the December 31, 2019 presentation.

We had no material contract assets, contract liabilities, or deferred contract costs recorded on the consolidated balance sheet as of December 31, 2019 and 2018. In addition, for the years ended December 31, 2019, 2018, and 2017, revenue recognized in the reporting period that was included in the contract liability balance at the beginning of the period is not material.

Revenue expected to be recognized in any future year related to remaining performance obligations is not material. As permitted in ASC Topic 606, we have elected to omit disclosure related to performance obligations for revenue pertaining to contracts that have an original expected duration of one year or less, to contracts where revenue is recognized as invoiced and to contracts with variable consideration related to wholly unsatisfied performance obligations.