Brass relational life table parameters by state over time review - Eddie Hunsinger, December 2018
Following code/steps by UToronto professor Monica Alexander as a template: https://github.com/MJAlexander/states-mortality/blob/master/lifespan_variation/lifespan.R (related blog post: https://www.monicaalexander.com/2018/12/21/lifespan-variation-as-a-measure-of-mortality-progress-and-inequality/)
Data is from the United States Mortality Database (https://usa.mortality.org/) (using the bundled lifetables.zip file)