Yup. I keep a tally of official Number One singles - sales-only to keep the list consistent as it began in the sales-only era - that are known or believed to have sold 300,000 or more copies in a single week, and also one for those which sold 30,000 copies or less. The latter listing currently has 53 occasions where the best-selling single (so since 2014 not necessarily the official combined sales/streams chart-topper) has registered 30K or under. Nine of those occurred during the first eight months of 2017 so far, with a further five having been accrued during 2016. It is getting harder and harder to keep up with, especially as this scenario is clearly going to become increasingly common as paid-for sales decline.
By contrast, the former table presently has 42 entries where 300K or above was recorded - none of which occurred in this or last year. Indeed, if we take the current decade for chart purposes to have begun in 2010, only four clocked up such impressive actual sales in the 2010s so far, all of which were either charity or X Factor-related. Honorary mention is made of 'Hello' by Adele which racked-up 333,944 units in 2015, but as my criterion is true paid-for sales only, it technically didn't count as it 'only' shifted 259,355 copies, the remaining 73,244 being derived from sales-equivalent streams at the 100:1 ratio. A notable achievement, especially for a 'regular' non-charity or talent show release, made all-the-more so by the rarity of such lofty sales figures being attained, even with streams factored-in at the SCR ratio.
So we haven't had a sales-only chart-topper that's turned in a 300K+ weekly return since 2014 when Band Aid 30's latest incarnation of 'Do They Know It's Christmas' managed 312,927 (plus 1 unit from streaming!). Whereas it was only last week when a 30K- figure came through - Luis Fonsi et al's 'Despacito' only limping to 17,677 copies, amazingly making it the best-selling track without streams, and the second worst total for a sales No 1 ever.
Even if I had compiled a comparable list which was inclusive of combined official No 1s, it would still be very clear to see where the trends are going here - not only a steady decline in real buys, but streamed rentals apparently not quite filling the gap left behind, albeit that titles on ACR will appear to be worse than if their full sales-equivalent total were counted at 150 (or 100):1.