MDU RESOURCES GROUP, INC. COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES Years Ended December 31, 1996 1995 1994 1993 1992 (In thousands of dollars) Earnings Available for Fixed Charges: Net Income per Consolidated Statements of Income $45,470 $41,633 $39,845 $38,817* $35,371 Income Taxes 16,087 23,057 18,833 19,982* 10,900 61,557 64,690 58,678 58,799 46,271 Rents (a) 1,031 894 878 871 504 Interest (b) 34,101 29,924 29,173 27,928 30,056 Total Available for Fixed Charges $96,689 $95,508 $88,729 $87,598* $76,831 Fixed Charges (c) $35,132 $30,818 $30,051 $28,799 $30,560 Ratio of Earnings to Fixed Charges 2.75x 3.10x 2.95x 3.04x* 2.51x * Before cumulative effect of accounting change of $5,521 (net of income taxes). (a) Represents portion (33 1/3%) of rents which is estimated to approximately constitute the return to the lessors on their investment in leased premises. (b) Represents interest and amortization of debt discount and expense on all indebtedness and excludes amortization of gains or losses on reacquired debt which, under the Uniform System of Accounts, is classified as a reduction of, or increase in, interest expense in the Consolidated Statements of Income. Also includes carrying costs associated with natural gas available under a repurchase agreement with Frontier Gas Storage Company as more fully described in Notes to Consolidated Financial Statements. (c) Represents rents and interest, both as defined above.