As discussed in Note 1, we primarily derive our revenues from the sales of various chemical products. The following table presents our net sales disaggregated by our principal markets, which disaggregation is consistent with other financial information utilized or provided outside of our consolidated financial statements:


	2019		2018		2017(a)
	(Dollars In Thousands)
Net sales:
Agricultural products	$	187,641	$	187,164	$	184,054
Industrial acids and other chemical products		139,643		148,598		196,029
Mining products		37,786		42,398		38,854
Other products		—		—		8,567
Total net sales	$	365,070	$	378,160	$	427,504

(a)

Upon adoption of ASC 606, nets sales have not been adjusted under the modified retrospective method.

Liabilities associated with contracts with customers (contract liabilities) primarily relate to deferred revenue and customer deposits associated with cash payments received in advance from customers for volume shortfall charges and product shipments. We had approximately $3.6 million and $7.0 million of contract liabilities as of December 31, 2019 and 2018, respectively. During 2019, revenues of $3.5 million were recognized and included in the balance at the beginning of the period.