population_data = csv.reader(open("population.dat","r"))

population_by_country_code = {}
for row in population_data:
    country = row[0]
    country_code = row[1]
    population_data = []
    for value in row[5:]:
        if value == "":
            population_data.append(None)
        else:
            population_data.append(float(value))
    country_data = {}
    country_data["country"] = country
    country_data["country_code"] = country_code
    country_data["population_values"] = population_data
    population_by_country_code[country_code] = country_data