That table may be a bit skewed. In general, as far as I know, many American companies START with two weeks (10 days) vacation and 3 personal days. It is true many people leave some on the table; I am not one of them.

I am, at this point, middle management. I get 4 weeks vacation, three personal days and usually 3-4 floating holidays. As far as sick time, mine is unlimited, so it's not a matter of taking/leaving. If you're sick, if you have surgery, you stay home. I also use one day every 7-8 weeks for my IV treatments, which is paid.

As far as leaving vacation on the table: so many American companies, my own included, are cut so close to the bone as far as personnel, you can't take off because there is just too much to do and no one to cover. It's a sad result of a combination of the economy and some very badly run companies, IMO.