Energy drink sales in the US

The US energy drink market and the US self-publishing industry grew together between 2010 and 2023 with a correlation of 0.974, which suggests either a shared customer base or a shared psychological condition. The working hypothesis is that the same person who cracks a can of something fluorescent at 11pm is also 40,000 words into a fantasy trilogy that will be available on Amazon by spring. The data cannot confirm this, but it cannot rule it out either.

US energy drink sales grew from roughly $8 billion in 2010 to over $20 billion by the early 2020s, driven by product proliferation, sports marketing, and the normalization of functional beverages. Self-published titles on platforms like Amazon KDP, Smashwords, and IngramSpark exploded over the same period, going from tens of thousands of titles annually in 2010 to over a million by the early 2020s, as digital publishing tools removed barriers to entry. Both markets were turbocharged by platform economics: Amazon created the infrastructure for both cheap e-book distribution and next-day Red Bull delivery. The gig economy, which grew strongly over this period, may also connect them — freelancers and side-hustlers index highly for both caffeinated stimulants and creative entrepreneurship.

Platform economies tend to democratize everything they touch at the same time, which means the beneficiaries of those platforms all start growing in unison. The correlation tells you something real about infrastructure, even if it tells you nothing about causation.