The CD is up fifty-nine per cent

Two days ago this section reported that 150,000 tracks a day are uploaded to streaming services and that a fifth of all recordings were streamed exactly zero times last year. Here is the same industry from the other end: the fastest-growing product in American music this year is a plastic disc in a jewel case.

The RIAA's mid-year figures put US recorded music revenue at about $6bn for the first half, up 6.9% on last year, as reported by Music Ally. Physical formats rose 25.9% overall. Vinyl grew 17.7% to $543.8m, and CD revenue rose 58.6% to $171.1m, from roughly $108m in the same period last year.

Streaming is still almost the entire business and nothing here changes that. What the physical numbers describe is a different transaction happening alongside it, and one with an economics the streaming business cannot replicate.

The arithmetic is the argument. A CD sold at $13 returns more to the rights holder than several thousand streams, and it returns it once, immediately, from a buyer who has decided to own a specific record rather than rent access to everything.

The CD's revival has an obvious cause and an unfashionable one. It is the cheapest way to own an album — vinyl has passed $35 a copy in many shops — and it is the format that a teenager discovering physical media can actually afford on pocket money.

There is a supply-side reason too. Vinyl pressing capacity is finite, lead times run to months, and an artist who wants a physical product for a release next quarter can get CDs made in weeks. Constraint at the prestige format pushes volume to the practical one.

Set this against the upload figures and the two trends look like the same story told twice. When recorded music becomes infinite and free at the margin, the scarce thing is not the recording but the object, the shelf and the decision to own something.

Independent shops are the channel that benefits most, and they are the part of the industry with the least leverage over streaming. A record store keeps the margin on a physical sale and the relationship with the buyer, neither of which any playlist provides.

The caution is that percentages on small bases flatter. CDs at $171m against a $6bn half-year is a rounding error in the industry's accounts, and one good half does not reverse two decades.

But the direction is the point. The industry spent twenty years planning for a future in which physical music was a souvenir, and the souvenir aisle is now the fastest-growing part of the shop.