My guess is that movement in the existing home inventory is a decent proxy total vacancies.

FORBES: Housing in 2013

In December employers reported total job vacancies of 3.4m, close to its highest since 2008.

ECONOMIST: Employment springs to life; will it fade again?

With another 100, 000 arrivals expected under a short-term visa scheme that allows employers to fill urgent job vacancies from outside Australia, the total intake is likely to be closer to 300, 000.

ECONOMIST: Where immigration is still booming