A family, by the numbers
How big is your Olin family? I don't know if it's as big as some of your other lines, but it is quite sizable.
The table below shows the size of the John Olin and Susannah Spencer family through 13 generations. Only direct descendants of John are shown -- no spouses.
The incremental column shows how many Olins there are in each generation. For example, the only Olin in generation 1 is John. The second generation consists of his 4 children, and so on.
The cumulative column shows the total number of Olins starting with John.
The middle column is the most interesting. As expected, each successive generation is larger than the previous one -- at least through generation 7. Generations 8 and 9 both show fewer people than their predecessors. Generation 10 shows a significant increase, and the following generations dwindle down to practically nothing.
What do the numbers tell us, if anything?
There are a couple easy conclusions we can draw. First, the last generation is going to be small because we're just getting to it. It wasn't too long ago that somebody gave birth to our first generation-13 cousin.
Second, look at generation 10, where the number jumped up. That's my generation, the Baby Boomers. Regardless of whatever else we learn, we would expect that generation to show an increase. [Note that depending on where you are on the family tree, the Boomers might be a generation other than 10. However, I think that the bump we see around generations 10 and 11 can be explained, at least in part, by the Boomers.]
Beyond that, it's not so clear. We would generally expect each generation to be bigger than the previous one, but birth rates have dropped at times, so maybe the numbers make sense.
My suspicion is that I'm simply missing data. I have a stack of data that still needs to be added to my database, and I'm confident that there are a lot of cousins whose existence is completely unknown to myself or other active family genealogists. It's interesting to note that the two major Olin histories of the 1890's both stop right around generation 8, where our numbers begin to fall. C. C. Olin's book stops with members of generation 8. George Nye's book includes just a handful of members of generation 9. After those two books, there were no major histories of the Olin family until a century later when Warren Olin published his 2-part history of the Joseph branch. I suspect large swaths of the John and Henry branches fell off our radar as a result.
The conclusion I draw from all this is what every genealogist knows: Our work is never done. We need to keep searching and digging to fill in the gaps in the story of our Olin family and to find those cousins who remain undiscovered.
In the meantime, consider inviting over all those cousins we do know about. Just be sure to make enough macaroni salad!