Table:
Years ended December 31,
2019
2018
Products and Licensing revenue
$44,491,041
$21,949,689
Technology Development revenue
26,024,674
20,967,556
Total revenue
$70,515,715
$42,917,245
Products and Licensing operating income
$1,807,616
$499,323
Technology Development operating income 
1,507,405
378,212
Total operating income
$3,315,021
$877,535
Depreciation, Technology Development
$397,296
$379,952
Depreciation, Products and Licensing 
$552,285
$273,185
Amortization, Technology Development 
$91,185
$130,765
Amortization, Products and Licensing
$1,462,525
$418,349

text: 17. Financial Information About Segments
text: Our operations are divided into two reportable segments: Products and Licensing and Technology Development. The Products and Licensing segment develops and sells products or licenses technologies based on commercially viable concepts developed by the Technology Development segment. The Products and Licensing segment derives its revenue from product sales, funded product development and technology licenses.
text: Our engineers and scientists collaborate with our network of government, academic and industry experts to identify technologies and ideas with promising market potential. We then compete to win fee-for-service contracts from government agencies and industrial customers who seek innovative solutions to practical problems that require new technology. The Technology Development segment derives its revenue primarily from services. The Technology Development segment provides applied research to customers in our areas of focus.
text: Our President and Chief Executive Officer and his direct reports collectively represent our chief operating decision makers, and they evaluate segment performance based primarily on revenue and operating income or loss.
text: Information about the results of operations for each segment is set forth in the table below. There were no significant inter-segment sales during the years ended December 31, 2019 and 2018.
text: During the years ended December 31, 2019 and 2018, 32% and 24%, respectively, of our total sales took place outside the United States. Customers in China represented 11% of total revenues in the year ended December 31, 2019, while no other single country, outside of the United States, represented more than 10% of total revenues in the year ended December 31, 2018.

Questions and answers:
question: What are the two reportable segments of operations?
answer: Products and Licensing and Technology Development.
question: What is the change in Products and Licensing revenue between December 31, 2018 and 2019?
answer: 22541352
derivation: 44,491,041-21,949,689
question: What is the average Products and Licensing revenue for December 31, 2018 and 2019?
answer: 33220365
derivation: (44,491,041+21,949,689) / 2
question: In which year was Products and Licensing revenue less than 25,000,000?
answer: 2018
derivation: locate and analyze Products and Licensing revenue in row 3
question: What was the Technology Development revenue in 2019 and 2018 respectively?
answer: 26,024,674
20,967,556
question: What was the Products and Licensing revenue in 2019 and 2018 respectively?
answer: $44,491,041
$21,949,689