The Company has two reportable operating segments based on two primary areas of service. The Engineering and Other Scientific segment is a broad service group providing technical consulting in different practices primarily in engineering. The Environmental and Health segment provides services in the areas of environmental, epidemiology and health risk analysis. This segment provides a wide range of consulting services relating to environmental hazards and risks and the impact on both human health and the environment. Our Chief Executive Officer, the chief operating decision maker, reviews revenues and operating income for each of our reportable segments but does not review total assets in evaluating segment performance and capital allocation.

Segment information for the three and nine months ended September 27, 2019 and September 28, 2018 follows:

	Three Months Ended				Nine Months Ended
(In thousands)	September 27, 2019		September 28, 2018		September 27, 2019		September 28, 2018
Engineering and Other Scientific	$	83,060	$	77,853	$	250,134	$	231,980
Environmental and Health		18,488		17,449		56,951		55,400
Total revenues	$	101,548	$	95,302	$	307,085	$	287,380

	Three Months Ended						Nine Months Ended
(In thousands)	September 27, 2019			September 28, 2018			September 27, 2019			September 28, 2018
Engineering and Other Scientific	$	27,925		$	25,784		$	83,151		$	77,499
Environmental and Health		6,175			5,401			19,410			18,181
Total segment operating income		34,100			31,185			102,561			95,680
Corporate operating expense		(10,916	)		(10,591	)		(38,800	)		(31,010	)
Total operating income	$	23,184		$	20,594		$	63,761		$	64,670

	Three Months Ended				Nine Months Ended
(In thousands)	September 27, 2019		September 28, 2018		September 27, 2019		September 28, 2018
Engineering and Other Scientific	$	664	$	1,878	$	3,371	$	3,982
Environmental and Health		17		43		73		141
Total segment capital expenditures		681		1,921		3,444		4,123
Corporate capital expenditures		4,197		2,795		14,675		9,542
Total capital expenditures	$	4,878	$	4,716	$	18,119	$	13,665

	Three Months Ended				Nine Months Ended
(In thousands)	September 27, 2019		September 28, 2018		September 27, 2019		September 28, 2018
Engineering and Other Scientific	$	1,179	$	1,102	$	3,470	$	3,318
Environmental and Health		55		44		148		124
Total segment depreciation and amortization		1,234		1,146		3,618		3,442
Corporate depreciation and amortization		438		415		1,286		1,268
Total depreciation and amortization	$	1,672	$	1,561	$	4,904	$	4,710

No single client comprised more than 10% of the Company’s revenues during the three and nine months ended September 27, 2019. One client comprised 12% of the Company’s revenues during the three months ended September 28, 2018. The same client comprised 14% of the Company’s revenues during the nine months ended September 28, 2018. No other single client comprised more than 10% of the Company’s revenues during the three and nine months ended September 28, 2018. No single client comprised more than 10% of the Company’s accounts receivable at September 27, 2019 and December 28, 2018.