Condensed Consolidated Balance Sheets - USD ($)	Nov. 30, 2022	May 31, 2022	Nov. 30, 2021
Current assets:
Cash and cash equivalents	$ 21,013,144	$ 22,517,038	$ 18,648,084
Short-term investments	1,097,450	1,097,450
Accounts and other receivables, net	5,940,731	4,466,686
Inventory	5,596,046	5,854,935
Costs and estimated earnings in excess of billings	5,295,376	3,336,474
Other current assets	890,506	704,436
Total current assets	39,833,253	37,977,019
Maintenance and other inventory, net	972,282	1,107,309
Property and equipment, net	10,610,010	9,854,759
Other assets	207,879	205,359
Deferred income taxes	74,615	74,615
Total assets	51,698,039	49,219,061
Current liabilities:
Accounts payable	1,537,181	1,426,830
Billings in excess of costs and estimated earnings	1,089,884	1,122,763
Other current liabilities	3,087,615	3,414,314
Total current liabilities	5,714,680	5,963,907
Stockholders' Equity:
Common stock and additional paid-in capital	10,495,584	10,329,258
Retained earnings	38,402,777	35,840,898
Stockholders’ equity before treasury stock	48,898,361	46,170,156
Treasury stock - at cost	(2,915,002)	(2,915,002)	(2,915,002)
Total stockholders’ equity	45,983,359	43,255,154	$ 41,773,752
Total liabilities and stockholders’ equity	$ 51,698,039	$ 49,219,061