Why is this rising

Sale 1

http://backpack.tf/profiles/76561198067417092?time=1448697600&compare=1448784000 Bulk for Blizz Cannon

Sale 2

http://www.tf2outpost.com/trade/27425338 Sold for 16 keys

B/O for Defiant was 19

X = 16

Keys https://gyazo.com/897a9b9b42a426cce0df264c8ae65bd1 http://backpack.tf/profiles/76561198106843393?time=1447574400&compare=1447660800

Spartan http://backpack.tf/item/761916786

Sale 3

http://www.tf2outpost.com/trade/27414061 Sold for G. Fetti Elfin

B/O for Defiant was 15

X = 15*0.9

X = 14

Elfin http://backpack.tf/item/3956970377

Defiant http://backpack.tf/item/1321235629

Trade http://backpack.tf/profiles/76561198068999011?time=1447315200&compare=1447401600

Sale 4

http://backpack.tf/profiles/76561198101229172?time=1446883200&compare=1446969600 Bulk for DBD Billy + P. Fetti Buckaroo's

Sale 5

[No OP Trade] Sold with 0.5 keys of sweets for C9 Bombing

Presumed Spartan was offered

X + 0.5 = 15

X = 15

Bombing http://backpack.tf/item/2026240730

Defiant http://backpack.tf/item/1321235629

Trade http://backpack.tf/profiles/76561198101229172?time=1446883200&compare=1446796800

Sellers

http://www.tf2outpost.com/trade/27592422 14 keys

http://www.tf2outpost.com/trade/27618008 14 keys