Addition of historical India GDP since 1960 (#129)
Addition of historical India GDP since 1960 (#129)

* Addition of Historical United States Population (since 1960)

* Addition of historical China population data (since 1960)

* Addition of historical USA GDP since 1960

* Addition of historical CHINA GDP since 1960

* Addition of historical India GDP since 1960

* Add country list for Worldbank datasets

* Add GDP to table of contents

* Add GDP to table of contents

jdorfman/Awesome-JSON-Datasets