13. MAJOR CUSTOMERS

Net sales for the years ended December 31, 2011, 2010 and 2009, include sales to the following major customers, together with the receivables due from the major customers:


				Net Sales			% to Total Net Sales
		Year Ended December 31,					Year Ended December 31,
		2011		2010		2009	2011		2010		2009
U.S. Government Agencies	$	6,890,444	$	8,291,418	$	7,337,768	34	%	36	%	35	%
Ministry of Energy and Water,
Afghanistan		2,268,219		686,133		982,286	11	%	3	%	5	%
Dominion/ADASA		1,159,686		1,880,323		2,317,998	6	%	8	%	11	%
Tamil Nadu Agricultural
University		131,778		372,982		2,357,331	1	%	2	%	11	%
	$	10,450,127	$	11,230,856	$	12,995,383	52	%	49	%	62	%


				Accounts Receivable			% of Total Accounts
		Amount at December 31,					Receivable at December 31,
		2011		2010		2009	2011		2010		2010
U.S. Government Agencies	$	1,460,810	$	1,183,509	$	1,315,195	22	%	22	%	18	%
Ministry of Energy and Water,											8	%
Afghanistan		1,447,536		577,035		593,841	21	%	11	%
Dominion/ADASA		563,487		49,151		2,108,081	8	%	1	%	28	%
Tamil Nadu Agricultural							-		3	%	20	%


University		12,398		144,632		1,461,170
	$	3,184,231	$	1,954,327	$	5,478,287	51	%	37	%	74	%

The above table includes unbilled accounts receivable. As of December 31, 2011 and 2010, unbilled receivables of $460,000 and $751,000 are included for Ministry of Energy and Water, Afghanistan. As of December 31, 2009, unbilled receivables of $1,068,000 and $1,040,000 are included for Dominion/ASDA and Tamil Nadu Agricultural University, respectively.

Because of the nature of the Company's business, the major customers may vary between years.