Who really carries more than one $100 bill at a time? Big purchases are made with card or dang near exact cash. So if you are buying a refrigerator you likely have the money for it and don't carry that kind of money around ALL the time, since you aren't buying major appliances all the time.
Unless it is a card of some sort, who really carries all their money on them all the time? Why do you need it all on you? You are going to drive by a car dealership and impulse buy a minivan? I have given thought and the majority of people don't have $500 or even $200 that they can carry around on them unless they are spending it then bringing the purchase back home.
$191 is what you have now if you have 1 of every bill. How often do you need that much money on you? Also many places wont take 50s and over, they jsut don't keep change in the cash drawer for that large a bill, especially the places most likely to get robbed, the gas station. They take a 50 if you get that much gas, but they rarely keep 20s in the drawer.
To decrease the amount of mugging the $1 and $2 coin would help but NOT making larger bills. Just let people learn to use coins again that have become complacent to plastic. For those wanting to look at the real economy, school lunches prices are going up and that is putting more kids on the "free lunch" program, so not many people can afford to own a $200 bill.
too few bills would be needed and they would most likely jsut go back and forth between banks like the $500 and $1000 was it would be no point at all since they just use digital transfers for most things like cards and checks. How many bills would a bank be stuck with before they sent them back? All bank I know need a "pack" worth of bills if they have to send out for more or jsut need to not have the excess on hand. Same goes for coins, Banks are stuck with EVERY half dollar coin until they have $500 worth, every $1 coin until they have $1000 to send to these coin rolling services.
Who would really use a $200 or $500 in this day and age? How often would you need to use one?