当我想从st.louis fed导入数据时，python给了我这样一个错误：长度不匹配：预期轴有8个元素，新值有7个元素。我可以通过删除dataframe的最后一列来解决这个错误，但我需要最后一列。我该怎么办？

import matplotlib.pyplot as plt
    import pandas_datareader.data as pdr
    import pandas as pd
    import datetime
    start = datetime.datetime (2000,1,1)
    end = datetime.datetime (2021,5,1)
    df  = pdr.DataReader(['WFRBSB50215', 'WFRBST01134','WFRBST01122', 'WFRBSN09139', 'WFRBSB50189', 'WFRBST01110','WFRBSB50191','WFRBSN09148'],'fred',start, end)
    df.columns = ['Share of Total Net Worth Held by the Bottom 50% (1st to 50th Wealth Percentiles)',
                  'Share of Total Net Worth Held by the Top 1% (99th to 100th Wealth Percentiles)', 
                  'Share of Corporate Equities and Mutual Fund Shares Helb By Top1%(99th to 100th Wealth Percentiles)', 
                  'Share of Financial Assets Held by the 90th to 99th Wealth Percentiles',
                  'Share of Total Assets Held by the Bottom 50% (1st to 50th Wealth Percentiles)',
                  'Share of Real Estate Held by the Top 1% (99th to 100th Wealth Percentiles)',
                  'Share of Real Estate Held by the Bottom %50(1st to 50th Wealth Percentiles)'
                  'Share of Mortgages Held by the 90th to 99th Wealth Percentiles']
    ax = df.plot(subplots=True, figsize=(12,12), linewidth=3.5, colormap="summer")
    plt.xlabel('Date')
    ax[0,].set_title('Share of Total Net Worth Held by the Bottom 50%')
    ax[0,].set_ylabel('Percent of Aggregate')
    ax[1,].set_title('Share of Total Net Worth Held by the Top 1%')
    ax[1,].set_ylabel('Percent of Aggregate')
    ax[2,].set_title('Share of Corporate Equities and Mutual Fund Shares Helb By Top 1%')
    ax[2,].set_ylabel('Percent of Aggregate')
    ax[3,].set_title('Share of Financial Assets Held by the 90th to 99th Wealth Percentiles')
    ax[3,].set_ylabel('Percent of Aggregate')
    ax[4,].set_title('Share of Total Assets Held by the Bottom 50% ')
    ax[4,].set_ylabel('Percent of Aggregate')
    ax[5,].set_title('Share of Real Estate Held by the Top 1%')
    ax[5,].set_ylabel('Percent of Aggregate')
    ax[6,].set_title('Share of Real Estate Held by the Bottom %50')
    ax[6,].set_ylabel('Percent of Aggregate')
    ax[7,].set_title('Share of Mortgages Held by the 90th to 99th Wealth Percentiles')
    ax[7,].set_ylabel('Percent of Aggregate')
    plt.tight_layout()
    plt.show()