What is the original source, and more importantly, methodology, of the data? It appears to reference [0], a 2017 publication, which itself references [1] a 201

What is the original source, and more importantly, methodology, of the data? It appears to reference [0], a 2017 publication, which itself references [1] a 2015 publication, which is a bit of a dead end from a layperson perspective. [0] https://www.who.int/publications/i/item/depression-global-health-estimates https://www.who.int/publications/i/item/depression-global-he... [1] https://ghdx.healthdata.org/record/ihme-data/gbd-2015-life-expectancy-all-cause-and-cause-specific-mortality-1980-2015 https://ghdx.healthdata.org/record/ihme-data/gbd-2015-life-e...