As an experiment, I wanted to find a good source for historical annual GDP data and see how easy it is to pull it into BOARD. I found the World Bank GDP dataset available on github as a CSV file. The source links are all at the bottom. I found it relatively easy to pull in the dataset, and also setup the relationships for some additional attributes. If you're looking for any GDP data, this should be something you can reuse as needed. This historical data goes back to 1960 for some countries, and up to 2017. As you can imagine, data for some countries is spotty, but I thought the World Bank is a well-recognized source. The datasource includes latitude and longitude coordinates to allow mapping. Countries are also grouped into regions by the admin region entity relationship.
If anyone has feedback on items I could have done differently, please let me know. Also, if you find this useful, please leave a suggestion of a future experiment I could do to help the community.