Driven this year by solid office demand growth in Sunbelt markets across the country, the national office occupancy rate is expected to increase into 2018 as such metros as Phoenix, Los Angeles, Atlanta and Miami enjoy net job growth in what’s already been one of the most drawn-out U.S. economic recoveries on record.

With slower than expected but steady job growth and muted levels of new construction, the U.S. vacancy rate fell to 10.5% in the…