100-150K before taxes is middle class. Upper middle class I think is 200K+ before taxes.
It really depends on the person, not on his income. Some are just really bad with their money. They make say 30k/year and spend it all, max out their cards and lease a merc to look rich. Especially the youth these days. I have a friend who's a waiter at a fast food joint and he spends everything on $500 dollar hoodies, shoes and wallets the moment he gets his paycheck. Some spend it entirely on sneakers. I have no doubt some spend their entire paychecks with SPs.
Some are just your average 50-75k guys that are single, young, unattached, addicted or in love with an SP. Instead of contributing for a downpayment or to retirement savings they spend most of their after tax, after rent income on SPs. Then finally you have your lawyers, consultants, businessmen, skilled tradesmen, doctors... which I believe contribute to the bulk of hobbyists that peruse girls at or above $250/hour or sometimes the occasional BP gem.
There will always be people who hide their income, especially ones who get paid in cash. You can't rely on Statcan for these things. There are also people who made their money elsewhere and heirs.