based on template from professor given, the colored circle represent the year level current ranged for every ten years, and the line represents the level change between each year.

dataset from: https://datahub.io/core/gdp-us

Gross Domestic Product of the United States (US GDP)

Gross Domestic Product (GDP) of the United States (US) both nominal and real on an annual and quarterly basis. Annual data is provided since 1930 and quarterly data since 1947. Both total GDP (levels) and annualized percentage change in GDP are provided. Both levels and changes are available both in current dollars (nominal GDP) and in chained 2009 dollars (real GDP). Data is sourced from US Government’s Bureau of Economic Analysis (BEA) and provided in standardized CSV.

Field Name Order Type (Format) Description
date 1 year The year
level-current 2 number GDP in billions of current dollars
level-chained 3 number GDP in billions of chained 2009 dollars
change-current 4 number GDP percent change based on current dollars
change-chained 5 number GDP percent change based on chained 2009 dollars