Professor Perry compares the per pupil cost of education to oil prices (both inflation adjusted).
Conclusion #1: Oil and gas prices in real dollars are about the same today in 2007 as in 1980, so we can conclude that petroleum prices have approximately doubled since 1929.
Conclusion #2: On the other hand, assuming the trend in spending increases for public schools in real dollars has continued over the last 5 years, the cost of educating a student in U.S. public schools is about 9X the cost in 1929.
Conclusion #3: Consider also the the quality of a barrel of oil or gallon of gas has probably remained the same since 1929, and we probably can't say that about the quality of public school education over the last 78 years. For example, see this 8th grade exam from 1895, how many high school students could pass this today?