6. Property and Equipment NOTES TO CONSOLIDATED FINANCIAL STATEMENTS Depreciation expense was approximately $15,070,000, $14,807,000 and $13,347,000 for the years ended December 31, 2002, 2001 and 2000, respectively. The Company leases certain land, buildings and equipment for use in its operations. Total rental expense charged to operations under operating leases was approximately $3,738,000, $4,072,000 and $4,054,000 for the years ended December 31, 2002, 2001 and 2000, respectively. Minimum rental commitments for all noncancelable operating leases at December 31, 2002 are as follows: The Company also leases equipment to customers under contracts generally ranging from 36 to 48 months. Rental income under such leases was $2,859,000, $2,846,000 and $3,908,000 for the years ended December 31, 2002, 2001 and 2000, respectively. Minimum rental payments to be received for equipment leased to others at December 31, 2002 are as follows: 8. Long-term Debt Long-term debt consisted of the following: December 31, 7. Leases December 31, Property and equipment consisted of the following: 2002 2001 Revolving credit loan of $58,200,000 at December 31, 2002, at interest rates from 4.7% to 6.5% at December 31, 2002 $ 31,902,204 $ 28,012,794 $80,000,000 Senior Secured Note due September 10, 2011, at 8.935%, payable in annual installments of $11,428,571 beginning September 10, 2005 80,000,000 80,000,000 Industrial Development Revenue Bonds payable in annual  installments of $500,000 through 2006 at weekly negotiated interest rates 2,000,000 2,500,000 Industrial Development Revenue Bonds due in 2019 at weekly negotiated interest rates 8,000,000 8,000,000 Industrial Development Revenue Bonds due in 2028 at weekly negotiated interest rates 9,200,000 9,200,000 Other current notes payable 2,762,265 1,940,394 Total long-term debt 133,864,469 129,653,188 Less current maturities 3,219,725 2,368,496 Long-term debt less current maturities $ 130,644,744 $ 127,284,692 2002 2001 Land, land improvements and buildings $ 86,636,858 $ 74,499,184 Equipment 111,476,360 106,544,080 Less accumulated depreciation (78,864,180) (67,562,056) Land, buildings and equipment - net 119,249,038 113,481,208 Rental property: Equipment 8,477,034 12,163,290 Less accumulated depreciation (1,926,793) (2,250,463) Rental equipment - net 6,550,241 9,912,827 Total $125,799,279 $123,394,035 2003 $2,132,171 2004 2,102,259 2005 942,733 2006 349,199 2007 261,910 Thereafter 277,723 2003 $ 1,585,504 2006 $ 1,457,577 2004 1,576,538 2007 1,265,570 2005 1,691,049 Thereafter 505,609