The current price for this doesn't correspond with the rules for non-unusual prices.

Bot.tf:

https://gyazo.com/6aeb055d7ae18f6b0b886f99fe368367 - base, 0 stats

https://gyazo.com/ab2fb7a1da18cd3bed36331c16e0600d - normal KS, 0 stats

https://gyazo.com/6fc977fde6261634f800fa6556b54ea0 - spec KS, 0 stats

Classified listings:

https://gyazo.com/bdb8a91b3bf29c9ed0e4a16c3ffdfb5f

Sellers at 17, buyers at 14.7.

Marketplace.tf:

Dec 2: $44.99 / $1.76 = 25.56 keys, 25.6 keys (outlier)

Nov 20: $30 / $1.75 = 17.14 keys, 17.1 keys

Nov 18: $21 / $1.72 = 12.21 keys, 12.2 keys (outlier)

Steam Market (key prices accurate to the hour):

Dec 5: $42.01 - $2.12 - 19 keys

Dec 4: $33.66 - $2.20 - 15.3 keys

Dec 4: 37.44 - $2.10 - 17.8 keys

Dec 1: 42.74 - $2.22 - 19.3 keys

Nov 29: $45.97 - $2.26 - 20.3 keys

Nov 24: $37 - $2.35 - 15.7 keys

Nov 22: $34.5 - $2.32 - 10.6

Nov 22: $45.47 - $2.33 - 19.5 keys

Nov 17: $46.24 - $2.38 - 19.4 keys

Nov 17: $43.12 - $2.36 - 18.3 keys

Nov 16: $37 - $2.37 - 15.6 keys

Nov 12: $44.21 - $2.34 - 18.9 keys

Nov 10: $35.15 - $2.33 - 15.1 keys

Nov 9: $39.99 - $2.35 - 17 keys

Nov 8: $39.72 - $2.32 - 17.1 keys

Conclusion:

Going with a range of 15.1-17.1. The 17.1 sales are close enough to the seller at 17 and the fact that there are both SCM and MPTF sales at 17.1 show that it should be included. Anything lower than 15.1 is countered by the buyers at ~15. Anything higher than 17 or 17.1 is countered by the seller at 17.