Past 30 days: https://gladiator.tf/sales?item=Strange%20Genuine%20Widowmaker&at=2021-07-11T18:15:40.389Z

One 10k 5r sale but countered by buyers, excluding.

Past month MP sales: https://marketplace.tf/items/tf2/527;1;strange

$39.99/1.85=21.6k

$39.99/1.89=21.2k

No other recent sales on other KS variants.

Past month SCM sales: https://steamcommunity.com/market/pricehistory/?country=US&currency=1&appid=440&market_hash_name=Strange%20Genuine%20Killstreak%20Widowmaker

$13.43/2.31=5.81k (very low, below buyers)

$19.98/2.24=8.92 (low, below buyers)

Pro KS sales: https://steamcommunity.com/market/listings/440/Strange%20Genuine%20Professional%20Killstreak%20Widowmaker

$29.96/2.41=12.4k (low, below buyers for pro ks)

$45.12/2.28=19.8k

$48.16/2.29=21k

Bulk trade:

https://backpack.tf/profiles/76561198091419784#!/compare/1623628800/1624752000

Taking range 19.8-21.6 keys.