7.9.1 ЯП ошибка нет значения года 1981 в списке

#7.9.1 ошибка нет значения года 1981 в списке
import pandas, seaborn
data = pandas.read_csv('crops_usa.csv')

acres = list(data['Acres'])
production = list(data['Production'])
years = list(data['Year'])

acres_usa = []
production_usa = []

for year in range(1980, 2020):
    acres_one_year = []
    production_one_year = []
    for index in range(len(data)):
        if years[index] == year:
            acres_one_year.append(acres[index])
            production_one_year.append(production[index])
    acres_usa.append(sum(acres_one_year))
    production_usa.append(sum(production_one_year))

yield_usa = []

for index in range(len(production_usa)):
    yield_usa.append(production_usa[index] / acres_usa[index])
years_numbers = list(range(1980, 2020))

error_acres = []

for index in range(len(production_usa)):
    error_acres.append(production_usa[index]-yield_usa[index-1]*acres_usa[index])

seaborn.barplot(x=years_numbers[1:], y=error_acres)
    # ваш код здесь