
	Payments Due By Period
(in thousands)	2020		2021		2022		2023		2024		Thereafter		Total
Purchase obligations (1)	$	33,237	$	9,482	$	3,751	$	2,565	$	3	$	4	$	49,042
Operating leases (2)
Lease obligations		12,879		10,776		10,947		10,350		9,004		21,858		75,814
Sublease income		(3,493)		(1,498)		(389)		(211)		(59)		(10)		(5,660)
Net lease obligation		9,386		9,278		10,558		10,139		8,945		21,848		70,154
Workers’ compensation obligations (3)		1,994		1,371		1,039		826		665		5,785		11,680
Total	$	44,617	$	20,131	$	15,348	$	13,530	$	9,613	$	27,637	$	130,876

(1)

Represents our purchase obligations primarily related to printing outsource agreements and capital expenditures for PP&E expiring at various dates through 2025.

(2)

Represents minimum rental commitments under operating leases with non‑cancelable terms in excess of one year and sublease income from leased space with non-cancelable terms in excess of one year. We rent certain facilities and equipment under operating leases expiring at various dates through 2028 and one parking lot through 2062. Total rental expense, included in other operating expenses, amounted to $17.6 million and $14.3 million in 2019 and 2018, respectively. Most of the leases provide that we pay taxes, maintenance, insurance and certain other operating expenses applicable to the leased premises in addition to the minimum monthly payments. Some of the operating leases have built in escalation clauses. We sublease office space to other companies under non-cancellable agreements that expire at various dates through 2025. Sublease income from operating leases totaled $4.4 million and $5.0 million in 2019 and 2018, respectively.

(3)

We retain the risk for workers’ compensation resulting from uninsured deductibles per accident or occurrence that are subject to annual aggregate limits. Losses up to the deductible amounts are accrued based upon known claims incurred and an estimate of claims incurred but not reported. For the year ended December 29, 2019, we compiled our historical data pertaining to the self‑insurance experiences and actuarially developed the ultimate loss associated with our self‑insurance programs for workers’ compensation liability. We believe that the actuarial valuation provides the best estimate of the ultimate losses to be expected under these programs. At December 29, 2019, the undiscounted ultimate losses of all our self‑insurance reserves related to our workers’ compensation liabilities were $11.7 million, net of estimated insurance recoveries of approximately $1.6 million. At December 30, 2018, the undiscounted ultimate losses of all our self-insurance reserves related to workers’ compensation liabilities were $12.3 million, net of estimated insurance recoveries of approximately $1.9 million.

We discount the net amounts above to present value using an approximate risk‑free rate over the average life of our insurance claims. For the years ended December 29, 2019, and December 30, 2018, the discount rate used was 1.6% and 3.1%, respectively. The present value of all self‑insurance reserves, net of estimated insurance recoveries, for our workers’ compensation liability recorded at December 29, 2019, and December 30, 2018, was $10.6 million and $10.7 million, respectively.