Results of Operations for the Years Ended December 31, 2019 and December 31, 2018
We reported revenues of $187.2 million for the year ended December 31, 2019, down 7.0% from $201.2 million for the year ended December 31, 2018. Our net loss was $15.6 million or $0.96 loss per diluted share for the year ended December 31, 2019 versus a net loss of $24.1 million or $1.50 loss per diluted share for the year ended December 31, 2018. Our year-over-year unfavorable performance was primarily driven by lower Restaurant/Retail hardware revenue and corresponding hardware support service revenue from our traditional tier 1 customers as one of these customers completed significant projects in 2018 which were not repeated in 2019. The Company partially offset these reductions with continued growth in Brink POS revenue, including related SaaS, hardware and support services. The 2018 net loss include a valuation allowance of $14.9 million to reduce the carrying value of our deferred tax assets.
Operating segment revenue is set forth below:
* Brink includes $0.3 million of Restaurant Magic for 2019
Product revenues were $66.3 million for the year ended December 31, 2019, a decrease of 15.8% from $78.8 million recorded in 2018. This decrease was primarily driven by lower revenues from our tier 1 customers and by a decrease in our international business. Our hardware sales in the Restaurant/Retail reporting segment were down versus prior year as we completed hardware project installations with a large domestic customer during the first half of 2018 which was not recurring in 2019. Additionally, international sales were down in 2019 and SureCheck was divested. SureCheck product revenue was $0.7 million in 2019 versus $2.0 million in 2018.
Service revenues were $57.0 million for the year ended December 31, 2019, an increase of 3.1% from $55.3 million reported for the year ended December 31, 2018, primarily due to an increase in Brink, including a $3.9 million increase in Brink POS SaaS revenue more than offsetting a reduction in Services to our traditional Tier 1 customers and SureCheck Services. Surecheck Service revenue was $2.7 million in 2019 versus $4.0 million in 2018.
Contract revenues were $63.9 million for the year ended December 31, 2019, compared to $67.2 million reported for the year ended December 31, 2018, a decrease of 4.8%. This decrease was driven by a 4% decrease in our Mission Systems revenue due to reduction of revenue on cost-based contracts and a 4% reduction in ISR revenues due to ceiling limitations in a large customer's funding.
Product margins for the year ended December 31, 2019, were 22.9%, in line with the 23.0% for the year ended December 31, 2018.
Service margins were 30.9% for the year ended December 31, 2019, an increase from 23.8% recorded for the year ended December 31,2018. ServicemarginsincreasedprimarilyduetoBrinkPOSSaaSandtheincreaseinprofitabilityinourfieldservicebusiness. During 2018 and 2019, impairment charges were recorded for SureCheck capitalized software of $1.6 million and $0.7 million, respectively.
Contract margins were 8.9% for the year ended December 31, 2019, compared to 10.7% for the year ended December 31, 2018. The decrease in margin was primarily driven by decrease activity in Mission Systems' better performing cost-based contracts.
Selling, general, and administrative expenses were $37.0 million for the year ending December 31, 2019, compared to $35.0 million for the year ended December 31, 2018. The increase is due to additional investments in Brink POS sales and marketing and increased equity and incentive compensation, partially offset by savings in other departments. SG&A expenses associated with the internal investigation for 2019 were $0.6 million as compared to $1.1M in 2018.
Research and development expenses were $13.4 million for the year ended December 31, 2019, compared to $12.4 million recorded for the year ended December 31, 2018. This increase was primarily related to a $2.1 million increase in software development investments for Brink offset by decreases in other product lines.
During the year ended December 31, 2019, we recorded $1.2 million of amortization expense associated with acquired identifiable intangible assets in connection with our acquisition of Brink Software, Inc. in September 2014 (the "Brink Acquisition") compared to $1.0 million for the year ended December 31, 2018. Additionally, in 2019 we recorded $0.2 million of amortization expense associated with acquired identifiable intangible assets in the Drive-Thru Acquisition, and $0.1 million of amortization expense associated with acquired identifiable intangible assets in the Restaurant Magic Acquisition.
Other (expense) income, net, was ($1.5 million) for the year ended December 31, 2019, as compared to other income, net of $0.3 million for the year ended December 31, 2018. Other income/expense primarily includes fair value adjustments on contingent considerations, rental income, net of applicable expenses, foreign currency transactions gains and losses, fair value fluctuations of our deferred compensation plan and other non-operating income/expense. In 2018, a $0.5 million gain was recorded for the sale of real estate. In 2019, there was a $0.2 million expense for the termination of the Brink Acquisition earn-out agreement compared to a $0.5 million benefit as a result of a reduction of contingent consideration related to the Brink Acquisition in 2018.
Interest expense, net was $4.6 million for the year ended December 31, 2019, as compared to interest expense, net of $0.4 million for the year ended December 31, 2018. The increase reflects $2.6 million of interest expense related to the sale of the 4.50% Convertible Senior Notes due 2024 issued on April 15, 2019 (the "2024 notes") as well as $2.0 million of accretion of 2024 notes debt discount for 2019.
For the year ended December 31, 2019, our effective income tax rate was 18.9%, which was mainly due to deferred tax adjustments related to foreign tax credit carryforwards and state taxes, offset by changes in the valuation allowance and excess tax benefits resulting from the exercise of non-qualified stock options. For the year ended December 31, 2018, our effective income tax rate was (141.7)% due to recording a full valuation allowance on the entire deferred tax assets.
Table:
 | Year ended December 31, |  | $ | %
(in thousands) | 2019 | 2018 | variance | variance
 Restaurant/Retail |  |  |  | 
   Core | $78,238 | $102,877 | $(24,639) | (24)%
Brink * | 41,689 | 25,189 | 16,500 | 66%
SureCheck | 3,380 | 6,003 | (2,623) | (44)%
 Total Restaurant Retail | $123,307 | $134,069 | $(10,762) | (8)%
 Government |  |  |  | 
   Intelligence, surveillance, and reconnaissance | $29,541 | $30,888 | $(1,347) | (4)%
Mission Systems | 33,513 | 35,082 | (1,569) | (4)%
Product Sales | 871 | 1,207 | (336) | (28)%
 Total Government | $63,925 | $67,177 | $(3,252) | (5)%


Question: What is the average Core revenue for 2018 and 2019?
Answer: 90557.5
Calculation: (78,238 + 102,877) / 2