Table of Contents contribution margin. Non-cash GAAP straight-line lease cost included in location operating expenses increased from $117.2 million for the six months ended June 30, 2018 to $198.1 million for the six months ended June 30, 2019. Over the same period, our consolidated locations grew from 279 as of June 30, 2018 to 507 as of June 30, 2019. For our mature locations, the impact of straight-lining of lease cost is typically not as significant. However, 70% of our locations as of June 30, 2019 were not mature, and many of the leases for these locations are in a “free rent” period. Once the maturity of our leases outpaces the growth of our portfolio of leases, we expect that the impact of straight-lining of lease cost will have the effect of increasing (rather than significantly decreasing, as it has in the past) contribution margin. How has contribution margin trended over time? Contribution Margin and Contribution Margin Percentage (in millions) 75