There’s some good analysis in Billboard this week of single-track sales figures in the US so far this year. It’s good news for Pharrell Williams, whose ‘Happy’ single has sold 5.9m units in the US alone in 2014 – well ahead of the 4.5m units sold by the top-selling single at this point last year, Robin Thicke’s ‘Blurred Lines’. But further down the top-sales chart, there’s malaise: the top 200 tracks this year have sold 25.5m units less than the top 200 at this point in 2013, out of a total sales decline of 105m units. “The upshot: this year’s 12.8-percent decline in track sales is falling mostly – albeit by a small margin – on the shoulders of the most popular tracks,” writes journalist Glenn Peoples. “Purchases of all types are down. Consumers’ embrace of streaming service has started to impact their digital purchasing habits.” We’ll be digging in to some streaming stats very soon to track any corresponding rise.