The Stockholm International Peace Research Institute's Arms Transfers Database provides a tool to download the data. By default, that output is an .rtf rich-text file — not so easy to analyze with your favorite spreadsheet or statistics software. Luckily, getting a CSV of the data isn't very difficult. Here's how.
To get all transfers for 2016, by seller, run this command in your terminal:
curl http://armstrade.sipri.org/armstrade/html/export_trade_register.php --compressed \
--data 'low_year=2016' \
--data 'high_year=2016' \
--data 'seller_country_code=' \
--data 'buyer_country_code=' \