Despite its cumbersome title, a new book called I checked what happened in Japan in One Day serves up a geeky numerical snapshot of what the nation does every 24 hours.

It has only been out since February but brokers already love it. Number of cans sold per day from vending machines? 42m. Average time spent each day on smartphones by female high school students? Six hours, six minutes. Daily per capita egg consumption? 0.9 (and second only to Mexico’s 0.97). Good or bad, say the sales desks, there’s a stock-specific story waiting to burst from every factoid.

One entry, though, is already out of date. Government data published last week showed Japan’s declining, ageing demographics have passed a line from which return is implausible. Deaths now outnumber births at an average rate of 1,000 a day. By the time the Olympic flame is lit in Tokyo in 2020, the indigenous population will have shrunk by some 842,000. More than 14 per cent of Japanese will then be aged over 75.