This isn't shown in the data in the article. That could be explained as the data only goes back to 1970 (that I could see, apologies if there's a way to go bac

This isn't shown in the data in the article. That could be explained as the data only goes back to 1970 (that I could see, apologies if there's a way to go back further that I missed). Is there any publicly available data source that backs this up?