Please answer the given financial question based on the context.
Context: |Fiscal Years||||
||2019|2018|2017|
|Statements of Operations:||||
|Revenue|100%|100%|100%|
|Cost of revenue|43%|50%|55%|
|Gross profit|57%|50%|45%|
|Operating expenses:||||
|Research and development|120%|79%|79%|
|Selling, general and administrative|86%|79%|81%|
|Loss from operations|(149)%|(108)%|(115)%|
|Interest expense|(3)%|(1)%|(1)%|
|Interest income and other expense, net|2%|1%|—%|
|Loss before income taxes|(150)%|(108)%|(116)%|
|Provision for income taxes|1%|1%|1%|
|Net loss|(151)%|(109)%|(117)%|
Results of Operations
The following table sets forth the percentage of revenue for certain items in our statements of operations for the periods indicated:
Impact of inflation and product price changes on our revenue and on income was immaterial in 2019, 2018 and 2017.
Question: What is the average proportion of cost of revenue as a percentage of the total revenue in 2018 and 2019?
Answer:
46.5