找出每12行的平均值，并将输出写入包含年份和平均值的新csv文件中

import csv

# 读取原始csv文件
with open('原始文件.csv', 'r') as file:
    reader = csv.reader(file)
    data = list(reader)

# 创建新的csv文件，并写入标题行
with open('新文件.csv', 'w', newline='') as file:
    writer = csv.writer(file)
    writer.writerow(['年份', '平均值'])

    # 遍历数据块
    for i in range(0, len(data), 12):
        block = data[i:i+12]

        # 计算平均值
        total = sum(float(row[1]) for row in block)
        average = total / 12

        # 写入年份和平均值
        year = block[0][0]
        writer.writerow([year, average])