Sales from services increased by $28 million to $1,054 million for the 2017 Second Quarter, compared to $1,026 million for the 2016 Second Quarter. Sales from services represented approximately 39% of consolidated net sales for both the 2017 Second Quarter and the 2016 Second Quarter. Sales from services increased primarily due to higher volume for Power & Propulsion. Sales from services increased $6 million due to business acquisitions, net of divestitures.
For the 2017 First Half, consolidated net sales of $5,401 million increased $384 million, or 8%, compared to the 2016 First Half. Organic sales increased by $299 million, or 6%, to $5,296 million for the 2017 First Half. Organic sales exclude $105 million of sales increases related to business acquisitions and $20 million of sales declines related to business divestitures. For the 2017 First Half, organic sales to the U.S. Government increased $310 million, or 9%, to $3,932 million, and organic sales to international and commercial customers decreased $11 million, or 1%, to $1,364 million.
Sales from products increased by $217 million to $3,278 million for the 2017 First Half, compared to $3,061 million for the 2016 First Half. Sales from products represented approximately 61% of consolidated net sales for both the 2017 First Half and the 2016 First Half. Sales from products increased by $114 million for Broadband Communication Systems, $87 million for Total Training Solutions, $54 million for Precision Engagement Systems and $38 million for Integrated Sensor Systems due to trends similar to the 2017 Second Quarter. Sales from products increased $72 million due to business acquisitions, net of divestitures, and $20 million for Aviation Products primarily due to deliveries of aviation recorders and traffic and collision avoidance systems for commercial airline customers. These increases were partially offset by sales decreases of $93 million for Aircraft Systems and $75 million for ISR Systems due to trends similar to the 2017 Second Quarter.
Sales from services increased by $167 million to $2,123 million for the 2017 First Half, compared to $1,956 million for the 2016 First Half. Sales from services represented approximately 39% of consolidated net sales for both the 2017 First Half and the 2016 First Half. Sales from services increased primarily by: (1) $60 million for Vertex Aerospace due to higher volume on the U.S. Army C-12 contract, USAF KC-10 contractor logistics support contract, aviation support for the U.S. Army rotary wing training aircraft at Fort Rucker and USAF training aircraft, (2) $20 million due to higher volume for Integrated Sensor Systems and (3) $13 million due to business acquisitions, net of divestitures. See the reportable segment results below for additional discussion of our sales trends.
Operating income and operating margin: Operating income for the 2017 Second Quarter increased by $65 million, or 26%, compared to the 2016 Second Quarter and includes a pre-tax gain of $42 million related to the sale of the property in San Carlos, California, in connection with the previously announced on-going consolidation of the EDD/ETI Traveling Wave Tube (TWT) businesses in the Communication Systems segment. Operating margin increased by 210 basis points to 11.4% for the 2017 Second Quarter, compared to 9.3% for the 2016 Second Quarter. Consolidation activities related to the EDD/ETI TWT businesses increased operating margin by 120 basis points consisting of: (1) a gain on the sale of the property in San Carlos, California, which increased operating margin by 150 basis points and (2) severance and restructuring expenses, which decreased operating margin by 30 basis points. Excluding these consolidation activities, operating margin increased by 90 basis points.
Operating income for the 2017 First Half increased by $66 million, or 13%, compared to the 2016 First Half and includes a pre-tax gain of $42 million related to the sale of the property in San Carlos, California, in connection with the consolidation of the EDD/ETI TWT businesses. Operating margin increased by 60 basis points to 10.5% for the 2017 First Half, compared to 9.9% for the 2016 First Half. Consolidation activities related to the EDD/ETI TWT businesses increased operating margin by 50 basis points consisting of: (1) a gain on the sale of the property in San Carlos, California, which increased operating margin by 80 basis points and (2) severance and restructuring expenses, which decreased operating margin by 30 basis points. Excluding these consolidation activities, operating margin increased by 10 basis points. See the reportable segment results below for additional discussion of operating margin trends.
Interest expense and other: Interest expense and other for the 2017 Second Quarter and 2017 First Half declined by $4 million, primarily due to $5 million debt retirement charge as a result of the redemption of $300 million aggregate principal amount of 3.95% Senior Notes due November 15, 2016 in the 2016 Second Quarter.
Effective income tax rate: The effective tax rate for the 2017 Second Quarter decreased to 24.2% from 26.0%, primarily due to the reversal of previously accrued amounts related to foreign tax matters.