Buy orders at 36.7+ keys, which is above the current range. Not sure why the snapshot shows differently to current buy orders: https://i.imgur.com/hrrcmjw.png

Last month on Marketplace.tf:

October 3rd: Sold at $65.55, $1.85 per key = 35.4 keys

September 25th: Sold at $70.00, $1.85 per key = 37.8 keys

September 25th: Sold at $95.00, $1.85 per key = 51.4 keys

September 24th: Sold at $100.00, $1.84 per key = 54.3 keys

September 17th: Sold at $79.00, $1.84 per key = 42.9 keys

Last month on SCM:

October 11th, 4PM: Sold at £72.03, £1.77 per key = 40.7 keys

October 8th, 3PM: Sold at £41.73, £1.72 per key = 24.3 keys

October 6th, 1AM: Sold at £73.29, £1.71 per key = 42.6 keys

October 5th, 11PM: Sold at £73.47, £1.72 per key = 42.7 keys

October 5th, 11AM: Sold at £69.45, £1.72 per key = 40.4 keys

October 5th, 9AM: Sold at £62.61, £1.73 per key = 36.2 keys

October 3rd, 8PM: Sold at £70.98, £1.74 per key = 40.8 keys

October 3rd, 1PM: Sold at £69.39, £1.74 per key = 38.9 keys

October 2nd, 8AM: Sold at £71.87, £1.74 per key = 41.3 keys

October 2nd, 1AM: Sold at £62.11, £1.76 per key = 35.3 keys

October 1st, 2AM: Sold at £72.88, £1.79 per key = 40.7 keys

October 1st, 1AM: Sold at £71.79, £1.79 per key = 40.1 keys

October 1st, 12AM: Sold at £57.66, £1.79 per key = 32.2 keys

September 27th, 8PM: Sold at £69.54, £1.80 per key = 38.6 keys

September 27th, 7PM: Sold at £68.62, £1.81 per key = 37.9 keys

September 24th, 4AM: Sold at £71.84, £1.78 per key = 40.4 keys

September 24th, 12AM: Sold at £69.88, £1.79 per key = 39.0 keys

September 22nd, 2AM: Sold at £68.12, £1.81 per key = 37.6 keys

September 21st, 9PM: Sold at £52.92, £1.80 per key = 29.4 keys

September 21st, 4PM: Sold at £68.14, £1.79 per key = 38.1 keys

September 20th, 1AM: Sold at £60.96, £1.78 per key = 34.2 keys

September 19th, 3AM: Sold at £65.58, £1.78 per key = 36.8 keys

September 18th, 2PM: Sold at £65.68, £1.78 per key = 36.9 keys

September 18th, 7AM: Sold at £52.27, £1.76 per key = 29.7 keys

September 18th, 5AM: Sold at £62.10, £1.75 per key = 35.5 keys

September 15th, 5PM: Sold at £55.38, £1.77 per key = 31.3 keys

September 14th, 8PM: Sold at £65.11, £1.77 per key = 36.8 keys

So the values are:

24.3, 29.4, 29.7, 31.3, 32.2, 34.2, 35.3, 35.4, 35.5, 36.2, 36.8, 36.8, 36.9, 37.6, 37.8, 37.9, 38.1, 38.6, 38.9, 39.0, 40.1, 40.4, 40.4, 40.7, 40.7, 40.8, 41.3, 42.6, 42.7, 42.9, 51.4, 54.3

Ignoring below 36.7 due to buy orders. Ignoring 51.4 and 54.3 as they seem like high outliers. This gives us a range of 36.7-42.9 keys. Rounding to 37-43 keys.

I didn't look at Basic/Spec Killstreaks in detail as there are a ton of sales on just standards, but a quick scan paints a similar picture.