(1)	At both June 30, 2021 and December 31, 2020, interest rates ranged from 3.3% to 7.0% at a weighted average rate of 3.9%.

The allocation of total debt between fixed and variable-rate as well as between secured and unsecured is summarized below (in thousands):


	June 30,		December 31,
	2021		2020
As to interest rate (including the effects of interest rate contracts):
Fixed-rate debt	$	1,782,960	$	1,798,419
Variable-rate debt		4,002		40,000
Total	$	1,786,962	$	1,838,419
As to collateralization:
Unsecured debt	$	1,453,858	$	1,488,909
Secured debt		333,104		349,510
Total	$	1,786,962	$	1,838,419

We maintain a $500 million unsecured revolving credit facility, which was amended and extended on December 11, 2019. This facility expires in March 2024, provides for two consecutive six-month extensions upon our request, and borrowing rates that float at a margin over LIBOR plus a facility fee. At both June 30, 2021 and December 31, 2020, the borrowing margin and facility fee, which are priced off a grid that is tied to our senior unsecured credit ratings, were 82.5 and 15 basis points, respectively. The facility also contains a competitive bid feature that allows us to request bids for up to $250 million. Additionally, an accordion feature allows us to increase the facility amount up to $850 million.

Additionally, we have a $10 million unsecured short-term facility, which was amended and extended on March 24, 2021, that we maintain for cash management purposes, which matures in March 2022. At both June 30, 2021 and December 31, 2020, the facility provided for fixed interest rate loans at a 30-day LIBOR rate plus a borrowing margin, facility fee and an unused facility fee of 125, 10, and 5 basis points, respectively.

The following table discloses certain information regarding our unsecured notes payable under our credit facilities (in thousands, except percentages):


	June 30,			December 31,
	2021			2020
Unsecured revolving credit facility:
Balance outstanding	$	—		$	40,000
Available balance		498,068			458,068
Letters of credit outstanding under facility		1,932			1,932
Variable interest rate (excluding facility fee)		—	%		0.94	%
Unsecured short-term facility:
Balance outstanding	$	4,002		$	—
Variable interest rate (excluding facility fee)		1.38	%		—	%
Both facilities:
Maximum balance outstanding during the period	$	40,000		$	497,000
Weighted average balance		2,725			74,311
Year-to-date weighted average interest rate (excluding facility fee)		0.94	%		1.0	%

Related to a development project in Sheridan, Colorado, we have provided a guaranty for the payment of any debt service shortfalls until a coverage rate of 1.4x is met on tax increment revenue bonds issued in connection with the project. The bonds are to be repaid with incremental sales and property taxes and a public improvement fee (“PIF”) to be assessed on current and future retail sales and, to the extent necessary, any amounts we may have to provide under a guaranty. The incremental taxes and PIF are to remain intact until the earlier of the date the bond liability has been paid in full or 2040. Therefore, a debt service guaranty liability equal to the fair value of the amounts funded under the bonds was recorded. As of both June 30, 2021 and December 31, 2020, we had $53.7 million outstanding for the debt service guaranty liability.

Various leases and properties, and current and future rentals from those leases and properties, collateralize certain debt. At June 30, 2021 and December 31, 2020, the carrying value of such assets aggregated $605.7 million and $634.4 million, respectively. Additionally, at both June 30, 2021 and December 31, 2020, investments of $6.0 million, included in Restricted Deposits and Escrows, are held as collateral for letters of credit totaling $6.0 million.

Scheduled principal payments on our debt (excluding $4.0 million unsecured notes payable under our revolving credit facilities, $21.6 million of a finance lease obligation, $(2.7) million net premium/(discount) on debt, $(3.9) million of deferred debt costs, $4.9 million of non-cash debt-related items, and $53.7 million debt service guaranty liability) are due during the following years (in thousands):


2021 remaining	$	2,799
2022		308,298
2023		348,207
2024		252,561
2025		294,232
2026		277,733
2027		53,604
2028		92,159
2029		70,304
2030		950
Thereafter		8,569
Total	$	1,709,416

Our various debt agreements contain restrictive covenants, including minimum interest and fixed charge coverage ratios, minimum unencumbered interest coverage ratios, minimum net worth requirements and maximum total debt levels. We are not aware of any non-compliance with our public debt and revolving credit facility covenants as of June 30, 2021.