Sale 1:

Sold for a Duped Purple Energy Milkman and a Genuine Jungle Booty

Math

(40 + 1.3) = 41.3 rounding to 41 keys

http://www.tf2outpost.com/trade/25349785

http://backpack.tf/profiles/76561198107949914?time=1427353200 (March 26th)

http://backpack.tf/profiles/76561198107949914?time=1427439600 (March 27th)

Sale 2:

Sold for a Frostbite Greased Lightning

(42.5*0.9) = 38.25 rounding to 38 keys

http://www.tf2outpost.com/trade/25501731

http://backpack.tf/profiles/76561198036255543?time=1428217200 (April 5th)

http://backpack.tf/profiles/76561198036255543?time=1428303600 (April 6th)

Sale 3:

Sold for a Searing Plasma Cosa Nostra Cap and a Pro Rescue Ranger kit

(30 + 5)*0.9 = 31.5 rounding to 32 keys

http://backpack.tf/profiles/76561197977395790?time=1430463600 (May 1st)

http://backpack.tf/profiles/76561197977395790?time=1430550000 (May 2nd)

Sale 4:

Sold for an Orbiting Fire War Pig

(68*0.9) = 61.2 rounding to 61 keys

http://www.tf2outpost.com/trade/25857981

http://backpack.tf/profiles/76561198100895756?time=1430982000 (May 7th)

http://backpack.tf/profiles/76561198100895756?time=1431068400 (May 8th)

Sale 5:

Sold with an Uncraft Summer hat and a Gentle Manne's Service for a PE Challenge

(84*0.9) - 8.4 = 67.2 rounding to 67 keys

http://www.tf2outpost.com/trade/25902935

http://backpack.tf/profiles/76561198043673399?time=1432882800 (May 29th)

http://backpack.tf/profiles/76561198043673399?time=1433487600 (June 5th)

Notes:

Mini for the Pro Rescue Ranger kit: ~5

3 sold for $11.46 on the SCM on the day of the sale

(11.5/2.4) = 4.79166667 rounding to 5 keys

http://steamcommunity.com/market/listings/440/Professional%20Killstreak%20Rescue%20Ranger%20Kit

Mini for the PE Challenge: ~73.5

http://backpack.tf/vote/id/5579f18bb98d88bd2a8b4593

Mini for the Duped PE Milkman: ~40

(126*0.9) - 46 - 30 = 40.1 rounding to 40 keys

http://backpack.tf/profiles/76561198005056455?time=1432450800 (May 24th)

http://backpack.tf/profiles/76561198005056455?time=1432537200 (May 25th)

Mini for the Duped Milkman:

Conclusion:

Because the only one on the market has a B/O of 70 and because the most recent sales are the 2 highest, I’m taking the final range at 61 - 67 keys.