The Zumper National Rent Index shows rising shelter costs for a one-bedroom apartment are not sustainable for the working poor. The median national one-bedroom rent for August was $1,486, up 11.8% over the same month last year, surpassing July's record high. 

Readers may recall we have focused on New York City's hot rental market for apartments that continues to set "record number of records." In the metro area, one-bedroom rents are up a staggering 40% year-over-year. A two-bedroom apartment is up 47%. Across all boroughs, Manhattan had the highest rent, climbing to another record high of $4,214, up 27% over last year. 

So it is no surprise that NYC tops the list with the most expensive rent. San Francisco, San Jose, Boston, and San Diego rounded out the list of the five most costly rents in the nation.