For example, while there are many more divorces now than there used to be, this in itself is a tad misleading because there are many more people in the marriageable age than there used to be. Hence, something like the rate per 1000 married women is a far more useful comparison than raw numbers. So, while there are many more times the number of divorces these days, the rate per 1000 married women is double from 1960 to 1991. This statistic is still hard to understand when one takes into account fewer people marrying and marrying at later ages. ALL of these societal changes affect the various rates and statistics.
Some data is more readily meaningful than others.
While i do not have the numbers off hand, the percentage of children living with only one parent has shot up in the past 30 years. That's a pretty easily understood fact with great meaning for children. Some much more than others. The most useful statistics allow for a nearly direct comparison over a great number of years to see what the trend really is. But we should never forget that we are dealing with complex phenomena.