Amazon defines this as:
Includes product sales and digital media content where we record revenue gross. We leverage our retail infrastructure to offer a wide selection of consumable and durable goods that includes electronics and general merchandise as well as media products available in both a physical and digital format, such as books, music, video, games, and software. These product sales include digital products sold on a transactional basis; digital product subscriptions that provide unlimited viewing or usage rights are included in Retail subscription services.
2014: $68.513 billion, 2015: $76.863 billion, 2016: $91.431 billion.
Last reported quarter 2019 Q2 it was $31.05 billion, up by 14% year-over-year from $27.16 billion. From $108.35 billion in 2017 it increased by 14% to $122.99 billion in 2018.
Source: Amazon Quarterly Results.