Historical Bordeaux Blends

I was wondering if someone knew where I could locate the historical blends in both the right bank and left banks wines. I am curious if there are any trends in the variations of the historical blends to how they are currently. For example Have the ranges been tighter for the past few years? Has there been a greater or lesser allowance in cabernet franc or petite vedot? Do the second wines have more leeway? I can compile all of the information by webscrapping from websites such as Jeff Leve’s but was hoping it was done.