Apartment vacancies at all time low

An interesting article from CNBC says apartment vacancies are at an all time low - less than 5%. Of course this is US statistics and doesn't mean the Chicago area is in the same situation. The link: http://www.cnbc.com/id/102770312
I attended a presentation yesterday from someone from the National Association of Home Builders and it was mentioned there will be over 4,000 apartment units added to Chicago and the suburbs in 2015. This should help with rents but it seems the appetite for rentals is still at an all time high.