The 2020 balance sheet of Dugan, Incorporated, showed current assets of $3,150 and current liabilities of $1,630. The 2021 balance sheet showed current assets of $3,000 and current liabilities of $1,605. What was the company’s 2021 change in net working capital, or NWC? (A negative answer should be indicated by a minus sign. Do not round intermediate calculations. )