Testing if the data shifted from a specific moment

I have a time-series dataset with millions of companies and the concentration of their respective industries during the last 20 years. However, I know that from 2007 to 2008 there were some changes in the classification system of the industries in the country that I'm analyzing that might have affected the concentration index of some industries.

There are 78 industry categories in my dataset and my questions are: how can I test if the distribution of the concentration of these industries has significantly changed after 2008 in comparison to the concentration before? How can I code this test in R?

The data looks like this:

Thanks for your help!