Leases

We lease office space and certain computer and related equipment using noncancelable operating leases. At December 31, 2016, future lease payments for operating leases with initial or remaining noncancelable terms of one year or more consist of the following:



2017	$	149.7
2018	137.1
2019	121.4
2020	91.3
2021	69.9
Thereafter	201.1
Total minimum payments required	$	770.5

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 2016, 2015 and 2014 was $207.5, $212.9 and $192.5, respectively.