I suspect that a lot of what the Q team does nowadays is run surveys of the population to see how many people are awake. They probably have polling centers working for them, perhaps unknowingly (for example, by making them survey the % of people who are vaccine hesitant, which indirectly indicates the % of people who are awake).

I also suspect that they won't have to wait until 4-6% of the population is awake before stepping in - rather, I think it's the actual act of the military stepping in (when they'll deem that a large enough percentage of the population is ready) that will wake the remainder of the population, though 4-6% will remain asleep for the rest of their lives.