| Year | Total Gallons | Total Cost ($) | Dollars per Gallon | Total Gallons | Total Cost ($) | Dollars per Gallon | Total Gallons | Total Cost ($) | Dollars per gallon |
| 1977 | 8,202,050,960 | 2,903,916,483 | 0.35 | 1,708,376,244 | 685,021,510 | 0.40 | 9,910,427,204 | 3,588,937,993 | 0.36 |
| 1978 | 8,446,117,404 | 3,263,013,081 | 0.39 | 1,741,918,058 | 736,334,915 | 0.42 | 10,188,035,462 | 3,999,347,996 | 0.39 |
| 1979 | 8,865,885,434 | 4,997,337,860 | 0.56 | 1,828,434,958 | 1,173,468,510 | 0.64 | 10,694,320,392 | 6,170,806,370 | 0.58 |
| 1980 | 8,519,233,124 | 7,365,449,059 | 0.86 | 1,747,306,343 | 1,789,650,487 | 1.02 | 10,266,539,467 | 9,155,099,546 | 0.89 |
| 1981 | 8,555,248,712 | 8,754,148,572 | 1.02 | 2,032,520,313 | 2,330,110,892 | 1.15 | 10,587,769,025 | 11,084,259,464 | 1.05 |
| 1982 | 8,432,465,245 | 8,163,485,612 | 0.97 | 1,967,732,863 | 2,126,116,797 | 1.08 | 10,400,198,108 | 10,289,602,409 | 0.99 |
| 1983 | 8,672,573,586 | 7,633,523,987 | 0.88 | 1,998,289,233 | 1,928,411,150 | 0.97 | 10,670,862,819 | 9,561,935,137 | 0.90 |
| 1984 | 9,625,957,783 | 8,127,915,961 | 0.84 | 2,286,407,440 | 2,056,280,795 | 0.90 | 11,912,365,223 | 10,184,196,756 | 0.85 |
| 1985 | 10,115,007,164 | 8,095,266,966 | 0.80 | 2,487,928,853 | 2,104,475,731 | 0.85 | 12,602,936,017 | 10,199,742,697 | 0.81 |
| 1986 | 11,137,330,715 | 6,074,822,748 | 0.55 | 2,544,996,263 | 1,556,485,079 | 0.61 | 13,682,326,978 | 7,631,307,827 | 0.56 |
| 1987 | 11,586,838,169 | 6,366,468,879 | 0.55 | 2,893,617,033 | 1,734,661,158 | 0.60 | 14,480,455,202 | 8,101,130,037 | 0.56 |
| 1988 | 11,917,904,314 | 6,239,740,324 | 0.52 | 3,262,824,143 | 1,880,466,123 | 0.58 | 15,180,728,457 | 8,120,206,447 | 0.53 |
| 1989 | 11,905,144,333 | 7,089,094,462 | 0.60 | 3,557,293,595 | 2,265,140,725 | 0.64 | 15,462,437,928 | 9,354,235,187 | 0.60 |
| 1990 | 12,212,038,348 | 9,331,892,128 | 0.76 | 3,937,659,786 | 3,283,651,970 | 0.83 | 16,149,698,134 | 12,615,544,098 | 0.78 |
| 1991 | 11,360,011,372 | 7,607,275,359 | 0.67 | 3,887,859,343 | 2,952,396,403 | 0.76 | 15,247,870,715 | 10,559,671,762 | 0.69 |
| 1992 | 11,597,830,877 | 7,168,068,463 | 0.62 | 4,079,248,760 | 2,804,675,554 | 0.69 | 15,677,079,637 | 9,972,744,017 | 0.64 |
| 1993 | 11,959,981,137 | 7,019,799,704 | 0.59 | 4,111,795,204 | 2,727,302,656 | 0.66 | 16,071,776,341 | 9,747,102,360 | 0.61 |
| 1994 | 12,500,554,450 | 6,777,734,286 | 0.54 | 4,325,403,339 | 2,625,222,896 | 0.61 | 16,825,957,789 | 9,402,957,182 | 0.56 |
| 1995 | 12,811,716,586 | 6,992,890,218 | 0.55 | 4,511,418,312 | 2,702,639,675 | 0.60 | 17,323,134,898 | 9,695,529,893 | 0.56 |
| 1996 | 13,187,304,771 | 8,541,525,986 | 0.65 | 4,658,093,078 | 3,334,986,877 | 0.72 | 17,845,397,849 | 11,876,512,863 | 0.67 |
| 1997 | 13,657,627,229 | 8,610,523,268 | 0.63 | 4,961,599,949 | 3,398,645,252 | 0.68 | 18,619,227,178 | 12,009,168,520 | 0.64 |
| 1998 | 13,303,135,194 | 6,680,002,210 | 0.50 | 4,915,461,051 | 2,631,144,628 | 0.54 | 18,218,596,245 | 9,311,146,838 | 0.51 |
| 1999 | 14,490,518,585 | 7,509,979,428 | 0.52 | 5,276,542,707 | 3,008,642,280 | 0.57 | 19,767,061,292 | 10,518,621,708 | 0.53 |
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