Around here (coastal Southern CA) they're brown with gray highlights and they look more chipmunk-ish in the face. It seems like I see more chipmunks than squirrels (or else I notice them more often because their racing stripe is cute).
Only Europe has the interesting looking squirrels.
Unfortunately it sounds like the gray squirrels are jealous of the red squirrel's cuter looks, so are causing a decline in the red's population.
I grew up in the country in a house surrounded by fields. We never saw squirrels or chipmunks around us even though there were still plenty of oak, pear, and apple trees (not to mention other crops for them to eat). It wasn't until just a few years ago that I realized the squirrels and chipmunks do not like the wide open fields because of owls and hawks.
"Where free unions and collective bargaining are forbidden, freedom is lost." - 1980 Republican presidential candidate Ronald Reagan
Probably 70/25/5 black/grey/red. From what I recall the black squirrels are dominant and will eventually push out the greys and reds.