# How to compute historical bond drawdowns from yields

I came across a very interesting article which shows a picture with the drawdowns bondholders would have faced by investing in Fixed Income since 1919.

However, the picture I get looks a bit different. I have assumed a bond with a 30yr maturity and rebalanced every month.

The data is based on the Moody's seasoned AAA yield https://fred.stlouisfed.org/series/AAA .

I do not understand how they computed the drawdowns. I thought it was the inverse formula of duration, but there is no duration information.