Oxygen saturation level - what's OK?

[1starwars2]

I am a middle aged asthmatic.
I recently got a finger pulse and oxygen level meter.
I saw Dr today (and got antibiotics and steroids) for a wheeze I can't shake.
I meant to ask the Dr what is a reasonable/concerning oxygen saturation level. It was 91% on Dr's meter.
Anyone know at what point I should be concerned as my asthma has been pretty rubbish this year and trying to monitor it.

In Scotland 96% and above is what we consider “normal”, less than that would trigger on our early warning score system when observations are recorded.

88% - 92% is described as lower target range for someone with COPD and other long term conditions where oxygen therapy to correct it wouldn’t be appropriate.

Maybe worth asking what “target range” you’re considered to be in OP

Thanks for the advice. I have booked a telephone asthma review in November (first available).
Apparently they will see me in person if necessary after that.