Since the same plots are not evaluated every year and only evaluated once in about five years the present yearly changes in the percentage of adequate regeneration is only comparing various areas against one another. The present data can not be used in any way shape or form to determine if the total habitat for a unit, or even an area of a unit, is increasing or decreasing.
Some areas of every unit had more regeneration then other areas from the very bigging of the studies so all the data available so far has done nothing more then collect the regeneration data over a larger range of the entire unit. It will be a few more years yet before any comparisons of the same sample plots can be evaluated or compared to see if the total habitat is improving or decreasing.

At this point all that can be evaluated is the sample of the plots visited for that year which is about one fifth of all survey plots. That provides a snapshot view of the habitat as poor, fair or good but it can’t be compared as an annual comparison like you are trying to do.