change_in_unemployment.py

# Convert the Date column back to string,
# find January 1st 2020, 
# only keep State and percent unemployed columns
# Set index to State
jan_emp = df[df['Date'].dt.strftime(date_format='%Y-%m-%d').str.contains('2020-01-01')][['State','Pct_Unemployed']].set_index('State')

# Convert the Date column back to string,
# find June 1st 2020, 
# only keep State and percent unemployed columns
# Set index to State
june_emp = df[df['Date'].dt.strftime(date_format='%Y-%m-%d').str.contains('2020-06-01')][['State','Pct_Unemployed']].set_index('State')

# Subtract the January data from the June Data
chg_emp = june_emp.subtract(jan_emp)