1) corruption.csv:

• annual_income
• corruption_index

2) cost of living.csv:

• cost_index
• monthly_income
• purchasing_power

3) richest_countries.csv:

• gdp_per_capita

4) tourism.csv:

• tourism_in_millions
• receipts_in_billions
• receipts_per_tourist
• percentage_of_gdp

5) unemployment.csv:

• unemployment_rate