Leases

We lease office space and certain computer and related equipment using noncancelable operating leases. At December 31, 2015, future lease payments for operating leases with initial or remaining noncancelable terms of one year or more consist of the following:



2016	$	141.5
2017	140.0
2018	127.2
2019	109.9
2020	84.3
Thereafter	245.8
Total minimum payments required	$	848.7

We have certain lease agreements that contain contingent payment provisions. Under these provisions, we pay contingent amounts in addition to base rent, primarily based upon annual changes in the consumer price index. The schedule above contains estimated amounts for potential future increases in lease payments based on the contingent payment provisions.

Lease expense for 2015, 2014 and 2013 was $212.9, $192.5 and $185.9, respectively.