Lets try

https://marketplace.tf/items/tf2/5757;6;td-527

x1 Nov 15 2023 $50.99 (median key price that day = 1.73) = 29.5 keys

x1 December 30 2023 $50.99 (median key price = 1.68) = 30 keys

Steam Market:

https://steamcommunity.com/market/listings/440/Widowmaker%20Strangifier

Sorry but doing this in my local currency (AUD):

$64.69 AUD Jan 26 6AM

$44.04 AUD Jan 21 4PM

Dec 25 12pm 63.09

Dec 26 12pm 60.73

Dec 24 12pm 38.37

Dec 15 12pm 63.19

Dec 9 12pm $62.93

Dec 7 12pm $38.02

Dec 5 12pm $62.24

Dec 2 12pm $37.89

Nov 30 12pm $53.02

Nov 26 12pm $61.50

Nov 25 12pm $53.87 (x2)

Nov 17 12pm $61.40

Nov 16 12pm $34.92

Nov 14 12pm $61.30

Nov 12 12pm $61.56

Nov 10 12pm $61.50

Nov 8 12pm $61.07

Nov 9 12pm $53.50

Nov 6 12pm $54.35

Since there are buyers at 16 keys (equiv to $50.56 on steam market) I will exclude the sales in the <$50 range

$1075.31 / 19 = an median price of $56.599 , which divided by the key scm price of $3.16 AUD = 17.91 keys

I'm excluding the marketplace.tf sales due to the current $50.99 one unsold for almost a month, and the 25 key seller unsold for a week https://i.imgur.com/MXh38xW.png