I can't tell you exactly how much is absorbed because there are so many variables. Do you have a spacer (like an Aerochamber)? That will ensure that more of the particles make it to the lungs, rather than ending up inside of your mouth and later swallowed. Also, be sure to rinse your mouth after taking your inhaler.
Your dose is tiny, so it's very unlikely that there is much of anything getting into your system. At one time, before my GERD surgery, my asthma doc had me on Flovent 230mcg/4 puffs/twice a day. Now that's a lot, and I do believe I got some systemic effects. Fortunately, since my surgery I'm on a more normal, Advair 115 two puffs twice a day, for maintenance.
I believe I remember that my asthma doc told me that one 5 day course of oral prednosone is equivalent to an entire year of a maintenance dose of inhaled steroids as far as its systemic effects. He was quite certain that inhaled steroids are insignificant in their effect on the rest of the body.
Your dose is very low. It's unlikely that it's doing anything other than helping relieve lung inflammation. If you are concerned, by all means, call your allergy/asthma office and ask the question to them.