I used to get shocked everytime i got out of my car....untill i got new tires. Its funny the elements required for static to be created. I worked in a lab once were we had to be almost 100% ESD free. we wore special shmocks shoe/wrist straps and the place even had a specail floor that costs somewere around a grand a foot.
I'm not sure i've noticed an increase but it is true that synthetics in clothing cause more. It's also dependent on the relative humidity and temp. as well.