The resulting table will show you comparable times
for different ages for the selected distance.
The table will consist of a column for each age.
Find the column for your desired age, then look down the column
to scan race times for the selected distance.
Read across to the leftmost column to get the comparable "open class" (30 years
or younger) time for the times in your selected column.
The percentage rating along the leftmost side of the column shows the percent that the age-adjusted time is of the (approximate) current world record for that distance. If you believe that the various world records are comparable, then you might argue that 90%, or 80%, or any percent of the world records are comparable. You can use the percentage ratings, then, to compare race performances at different distances.