I have a database which contain years, car model and annual service cost. Each car had a service cost each year along with other data. I need to find out how to calculate the increase of values for each model over the years.   The database looks like this (simplified), contains about 10000 observations: Year Type Value Others 2020 Toyota $ 20000   2019 Toyota $ 16000   2018 Toyota $ 14000   2017 Toyota $ 14000   2020 Audi $ 20000   2019 Audi $ 18000   2018 Audi $ 17000   2017 Audi $ 15000     The results should be look like this: Type Change in $ from 2017 to 2020 Average change per year in $               My apologies I am a beginner, unfortunately I am not even sure how to approach this problem. Thank you for any help on this. I could not find anything similar to this problem here.   ... View more