Each agency shall keep a detailed account of all receipts and expenditures under such appropriate headings, classifications and arrangements as may be prescribed by the Director of the Office of Management and Budget and used in the budget estimates. All bills, statements, letters, vouchers and documents pertaining to these receipts and disbursements shall be preserved and systematically filed by each agency.

37 Del. Laws, c. 81, § ?16; Code 1935, § ?5414; 42 Del. Laws, c. 204, § ?6; 29 Del. C. 1953, § ?6504; 54 Del. Laws, c. 39, § ?4; 75 Del. Laws, c. 88, § ?21(13);