Well my understanding was:
DEFCON 5 to 4 is peace time.
DEFCON 3 to 2 is conventional war.
DEFCON 1 is nuclear war.
So if you remain on DEFCON 5 for this country /city (Gaza) I think you are wrong, but on a global scale, I don't know how you calculate that.
Like you calculate an average of how many countries are at war or you only count the nuclear armed countries being at war with each other.
And ignore the non nuclear countries. Or you just say: I don't care about them and or I don't care about this region or what ever your rules are and you stay at DEFCON 5 no matter what.
Every DEFCON level is applicable only to nuclear war. Conventional war does not enter into the equation unless it is a direct conventional war between two nuclear-armed powers which has the potential to escalate. This why most of the wars of the past 70 years have been proxy wars fought in less-developed countries: Korea, Vietnam, Afghanistan (Soviets), and Syria, to name a few.
DEFCON 5 is peace time, with no imminent nuclear threats.
DEFCON 4 is the same as DEFCON 5, except something of interest is happening that requires more detailed intelligence gathering.
DEFCON 3 is where it starts to get interesting, because the possibility of an actual nuclear exchange is now on the table and strategic forces are preparing for that possibility, following pre-arranged and well-reheasred protocols.
DEFCON 2 means that a nuclear exchange has moved from "possible" to "likely," and strategic forces are now on high alert ready to deploy nuclear weapons at a moment's notice. However, note that according to US Command & Control protocols, nuclear weapons still cannot be released at this stage even with a valid, authenticated launch order.
DEFCON 1 means that nuclear war is either imminent or already under way. Strategic forces will receive authorization codes to release nuclear weapons with pre-determined target packages based on who the enemy is. Nuclear weapons can be released upon receipt of a valid launch order from the National Command Authority.
Since Gaza possesses no nuclear weapons whatsoever, there is zero chance of a nuclear exchange occurring no matter what Israel does to them conventionally. Hence, the reason we are still at DEFCON 5. If Iran were to get militarily involved, that might change the situation since there is legitimate suspicion of Iran already possessing nuclear weapons. But if it remains localized between Israel and Palestinians, there is zero chance for it to escalate to a nuclear scenario.
I suggest you read our FAQ page on the exact definition of each DEFCON level and the steps you should be taking to prepare and protect yourself at each level.