Upper West Side rents rose in May and are way up over last year’s numbers — the average one-bedroom in a building without a doorman, for instance, will cost you 11% more than it did in May 2010, according to a new report on rental rates from MNS Real Impact Real Estate. On a month over month basis, rates rose for every apartment size, except two bedrooms in non-doorman buildings, where they fell 2.9%.

But vacancies are up this month meaning that rents could always fall in the future as landlords attempt to fill their empty apartments.

Are you getting a good deal? Check out the average rental rate for six different apartment classifications below:

• Studio (with doorman) $2,353
• Studio (no doorman) $1,924
• One-bedroom (with doorman) $3,410
• One-bedroom (no doorman) $2,549
• Two-bedroom (with doorman) $5,819
• Two bedroom (no doorman) $3,322

Photo by Ed Yourdon via flickr.