Theres a big difference between odds of a single event outcome and probability of outcomes over many equal events,
The same odds may apply on every attack
But
The more attacks you make without a certain result, no matter how low the odds of that result, the probability of that result occurring increases
I forget the formula, High School Math was a long time ago but I'm sure someone will be bored enough to look it up

Attack Mercs Killed (30) 459,329,001
Defence Mercs Killed (10) 2,918,478,517
Attack Soldiers Killed(60) 12,677,958
Defence Soldiers Killed(20) 226,236,488
Attack Super Soldiers Killed(300) 490,627,262
Defence Super Soldiers Killed(100) 4,131,482,551
Spies Killed(50) 4,256,505,842
Spy Killers Killed(50) 651,022,448
Mothership Weapons Destroyed(300) 35,583,034
Mothership Shields Destroyed(300) 39,498,511
Mothership Fleets Destroyed(200) 2,413,254
Planet Defences Destroyed(300) 358,539
Planets Taken(5000) 411
Naquadah Stolen(0.0001) 2,355,738,435,154,805
Untrained Kidnapped(50) 5,943,886,456
Weapon Points Destroyed (Sab+Att)(0.0001) 74,293,522,376,607
Attack Turns Used(1) 1,731,971