IDENTIFIED INTANGIBLE ASSETS AND LIABILITIES

Our identified intangible assets (acquired in-place and above and below-market leases) and liabilities (acquired below-market leases), net of accumulated amortization were $91.3 million and $184.1 million as of September 30, 2017, respectively, and $30.9 million and $147.0 million as of December 31, 2016, respectively.

Amortization of acquired below-market leases, net of acquired above-market leases resulted in additional rental income of $2.7 million and $6.8 million and for the three and nine months ended September 30, 2017, respectively, and $2.2 million and $6.0 million for the same periods in 2016.

Amortization of acquired in-place leases and customer relationships resulted in additional depreciation and amortization expense of $2.9 million and $6.0 million for the three and nine months ended September 30, 2017, respectively, and $0.8 million and $1.6 million for the same periods in 2016.

Certain shopping centers are subject to ground leases or ground and building leases. Amortization of these acquired below-market leases resulted in additional rent expense of $0.2 million and $0.7 million for the three and nine months ended September 30, 2017 and 2016, respectively.

The following table sets forth the estimated annual amortization expense related to intangible assets and liabilities for the five succeeding years commencing January 1, 2018:



(Amounts in thousands)	Below-Market		Above-Market				Below-Market
Year	Operating Lease Income		Operating Lease Expense		In-Place Leases		Ground Leases
2018	$	12,074	$	1,574	$	11,285	$	972
2019	11,620		1,294		8,592		972
2020	11,453		1,016		7,325		972
2021	11,251		803		6,013		622
2022	10,802		426		4,224		590