For example: let us presume the report stated:
Graduation From Grade School was up 5% from 1981 to 1991.
You would think from this report that the average kid had 5% greater chances of getting a Grade School Diploma in 91 than in 81. . .but. . .it turns out that it was just the opposite because the population was 1.097352 times larger in 91, than it had been in 1981. . .which is about 10% larger, thus in a "real education" sense, in the same way the monetary reports are given in "real dollars" or "constant dollars," education was actually moving in just the opposite direction, and thus was DOWN about 5% instead of UP about 5% from 1981 to 1991.
Remember, these were not from years quoted in the report and the figures were not exactly 5% or 10% respectively, nor the diploma referred to was not a Grade School Diploma, but they are pretty close to being exact, in terms of the percentages and years; much closer than you might expect.
***Here is a footnote explanation of how to be more exact***
To be exact, one would have to do a demographic analysis, of the specific portions of the population of the ages at which such diplomas were conferred, as it would be irrelevant from a realistic point of view to measure the population on whole bases if you were only concerned with people who were of the age to receive Kindergarten Diplomas between 1981 and 1991— or whatever ages and a whatever kind of diploma. Thus these figures are not as precise as they could be, but still given the trends of population and education, it is obvious that a trend in one is not following the direction of the other. A further look at the US Census figures averaged below will be sufficient to inform you that previous generations that were measured had even greater growth rates than 10%, so that the number of people getting any specific degrees or diplomas in the following decades should have been going up even more.
***
In the tables below, the first line shows the Base Year: or
"The Year In Question" labeled "YEAR: ####" so if you want a
chart based on 1980 as the base year, you simply search/find
"YEAR: 1980" to find the relevant portions.
Once you have located the table for "YEAR: ####" you can see comparisons of that year to any other year by looking up the year you wish to compare to in the left column.
The SAMPLE comparison is 1991, presented below.
You will note a ten year comparison looks like: