The Publishers Association's half-year e-book numbers show fiction e-book sales up 188% over 2011, helping to contribute to a market that seems remarkably robust.

The PA will have been pleased by the headlines, and in particular by this blog from the BBC's technology correspondent Rory Cellan-Jones: "take two industries trying to adapt to the digital era, music and publishing. One is packed with bright young ruthlessly ambitious people who have to be aware of the latest trends - the other is, well, publishing. So which is coping better? Publishing, believe it or not." (sic).

It is difficult to dig beneath the numbers from the press release sent by the PA, but the headline figures also show a different story to the one the wider media is interested in: that is a slowdown in the rate of growth (at least of fiction e-book sales), as we have seen in the US for sometime now, and which we may now be getting a hint of over here. According to past PA Stats Year Books, sales of digital fiction have been accelerating over the years, up 331% in 2011, after growing 299% in 2010, and 277% in 2009. Now they are up, in this half-year, by 188%.

This time last year the PA told us that general consumer e-books and downloads grew by 623% between January and June, compared with growth of 318% in 2010. The PA doesn't give an equivalent figure this time around, though one can deduce that it is also around the 180% mark.

The absolute numbers, of course, are much bigger than they were: the consumer e-book market showed sales of £84m in the first half, compared to sales of £92m in the whole of 2011, spending on digital fiction books was worth £64m so far this year (compared to £70m for the whole of last year).

And some might find the rate of growth academic, given the larger numbers we are now dealing with. Add to that, with Nook coming into the UK, the Waterstones Kindle deal reaching stores from October, and the spread of Kobo devices, we cannot yet take our eyes off this market or predict what these figures will do over the months ahead.