I am interested in understanding how the global population pyramid has changed in the last couple of centuries. 

I have two questions:

1) Has this been calculated? Are there estimates of population pyramids from the 19<sup>th</sup> century? Or from the beginning of 20<sup>th</sup> century? The earliest I have seen is 1950 ([below][1]).

2) If it hasn't been done, how can I construct it? It should be possible to model the population dynamics using birth and death rates (I would be surprised if this hasn't been done, as it has many applications outside of demography - e.g. economics). 

[![enter image description here][2]][2]

  [1]: https://ourworldindata.org/world-population-growth/#how-will-the-global-demography-will-change
  [2]: https://i.sstatic.net/p4R0W.png