We lease 442 sites from third parties under certain non-cancelable operating leases that expire from time to time through 2041. The weighted-average remaining lease term was 4.5 years as of December 31, 2023.

Lease expense was classified in the consolidated statements of income as follows (in thousands):


	Year Ended December 31,
	2023		2022		2021
Cost of sales	$	22,338	$	23,457	$	23,765
Operating expenses		15,460		15,254		13,531
General and administrative expenses		995		931		1,331
Total	$	38,793	$	39,642	$	38,627

Variable lease payments based on inflation or fuel volume included in the table above totaled $4.6 million, $4.4 million and $4.2 million for 2023, 2022 and 2021, respectively. Short-term lease payments included in the table above that are excluded from the lease liability amounted to $0.2 million, $0.2 million and $0.1 million for 2023, 2022 and 2021, respectively. Cash paid for amounts included in the measurement of lease liabilities under operating leases totaled $34.0 million, $35.0 million and $34.3 million for 2023, 2022 and 2021, respectively.

As of December 31, 2023, future minimum rental payments under operating leases, excluding variable lease payments or short-term payments, were as follows (in thousands). The weighted-average discount rate as of December 31, 2023 and 2022 was 5.8% and 6.0%, respectively.


	Third Parties		Related Parties		Total
2024	$	25,796	$	10,152	$	35,948
2025		23,565		10,310		33,875
2026		20,510		10,395		30,905
2027		16,202		8,953		25,155
2028		11,806		8,382		20,188
Thereafter		28,745		9,350		38,095
Total future payments		126,624		57,542		184,166
Less impact of discounting						30,656
						153,510
Current portion						34,787
Long-term portion					$	118,723

Most lease agreements include provisions for renewals. We generally do not include renewal options in our lease term for purposes of measuring our lease liabilities and right-of-use assets unless the sublease to our customer extends beyond the term of the head lease.

Of our leased sites, we operate 127 of them as company operated sites. Substantially all the remaining leased sites are subleased to lessee dealers or commission agents under leases with terms generally ranging from one to ten years and which may include renewal options. Sublease rental income amounted to $35.3 million, $35.4 million and $34.5 million for 2023, 2022 and 2021, respectively.

Motor fuel stations are leased to tenants under operating leases with various expiration dates ranging through 2037. Most lease agreements include provisions for renewals. We generally do not include renewal options in our lease term. Future minimum rental payments under non-cancelable operating leases with third parties as of December 31, 2023 were as follows (in thousands):


2024	$	45,941
2025		38,157
2026		27,715
2027		18,232
2028		12,002
Thereafter		13,143
Total future minimum lease payments	$	155,190

The future minimum rental payments presented above do not include contingent rent based on future inflation, future revenues or volumes of the lessee, or non-lease components for amounts that may be received as tenant reimbursements for certain operating costs.

Deferred rent income from straight-line rent relates to the cumulative amount by which straight-line rental income recorded to date exceeds cash rents billed to date under the lease agreement and totaled $5.0 million and $5.1 million at December 31, 2023 and 2022, respectively.