The amount of work that once bought an hour of light now buys 51 years of it

Image Source: https://www.washingtonpost.com/news/wonk/wp/2017/06/26/the-amount-of-work-that-once-bought-an-hour-of-light-now-buys-51-years-of-it/

The Washington Post article mentions a 1994 research paper by William Nordhaus as the source, but their link doesn't seem to work. Here's a working link to the paper:https://cowles.yale.edu/sites/default/files/2022-08/d1078.pdf