For the years 1980 to 1989 the data sources are
EIA
and
IEA (imports/exports).
For the years 1990 to 1999 the data sources are
EIA
and
IEA (imports/exports).
For the years 2000 to 2007 the data source is
Ember.
For the years 2008 to 2013 the data source is
IEA.
For the years 2014 to 2021 the data source is
Ember.