It's a complicated, but fair question. To answer it, one would need to know how many that were killed were Christians. It may seem cruel, but with a few exceptions, non-believers don't qualify for God's protection. Secondly, how many that were Christian were living lives that didn't block God from stepping in (I wish Christians and especially 20 somethingers would wake up to this).
This is probably a good spot to tell about an experience of maybe a dozen I've had with my angel. At the time, I had been a Christian about three years.
Back in the mid 70's, I operated a shop machine that was about as old as I was that had precious little in the way of safety guards.
One day, I dropped a plastic widget* into the bowels of this thing. I knew it had landed on exposed electrical terminals so I turned it off at the control panel switch and reached inside to retrieve the widget*. I was going to have to feel for it since it was too dark to see anything.
After reaching about halfway to it, an invivsible hand wrapped around my wrist and gently, yet firmly, kept me from reaching any further.

I withdrew my hand, thought about this a minute, then decided it was just my imagination or something, and made a second attempt. Again a hand wrapped around my wrist and kept me from reaching further. My Momma didn't raise no fools. I was now pretty sure this was an angel and something was wrong enough for him to do this. Just to be absolutely sure I reached in a third time but only to see if it happened again. Either way, I had no intention of touching anything. Again the hand stopped me.
I'm paying attention now and wondering why he kept doing that. Then, my attention was drawn to the power outlet in the wall and saw that it was still plugged in. I unplugged it, got a flashlight and retrieved the widget* like I should have the first time. The thing is that I had worked on that machine many times by just turning it off. When I looked into it, I realized the widget* had landed in an area I hadn't worked on before. It had landed on terminals that circuit-wise, were on the incoming side of the control panel switch. I was about to touch live 440 volt terminals while also grounded to the steel frame of the machine by leaning on it.
BTW, I learned my lesson. I still use similar, but safer versions of that machine. I don't touch the insides without pulling the plug whether it's necessary or not.
*widgets are the same thing as thingamabobs and dohickies.