Below are two plots resulting from playing around with Seaborn and running data from runalyze.com.
Actually, it is just every finisher of the Tour de France between 1903 and 2017. It was quite a pain to gather all the data and had to be done manually to some extend. Therefore it is entirely possible that some errors were made. I will give a detailed description for the generation of the data set. All used scripts and the final data can be found on Github. The picture above shows that the Tour is getting shorter and faster.