Inspired by a graphic in a Facebook group, I have expanded my existing records to show the increase of the Y-haplogroup I-S2599, to which I-L38 belongs, over the centuries. The result is an interesting picture that I would like to share with you. Most of the data used comes from the site discover.familytreedna.com and has been supplemented in a few places with data from YFull.com. Please note that these are only estimated values and contain a certain degree of inaccuracy.
I-S2599, along with I-M223, is a sub-branch of the Y-haplogroup I-P214 (I-M436), whose common ancestor lived around 18,000 years ago. It was not until around 4800 years ago that I-L38 grew out of it and over the centuries a small but fine Y-haplogroup developed. Until a few years ago, there was no further branching between I-P214 and I-L38, but a long bottleneck of over 13,000 years. The number of branches known today is very low and is indicated in the diagram as PRE 3000 BC.
The bars in the chart show the number of newly formed branches, including generic branches, of the respective main subgroups per century.
The line shows the percentage increase in the total summed branches of I-S2599 per century.