Write detailed pseudo code for a program that is designed to organize a family's tax payments for the past 20 years. The program should accomplish the following tasks:
- Prompt the user for the tax amount and also the year.
- Use appropriate data structure to store the tax amount and the year.
- Use a linear search algorithm to determine which year the family paid the highest tax, and display the result.
- Calculate the average amount of tax paid over the years, and display the result.