“Large Stocks” in Table 5.2 refers to Standard & Poor’s market-value-weighted portfolio of 500 U.S. common stocks with the largest market capitalization. “Small Stocks” represents the value-weighted portfolio of the lowest-capitalization quintile (that is, the firms in the bottom 20% of all companies traded on the NYSE when ranked by market capitalization).Since 1982, this portfolio has included smaller stocks listed on the Amex and Nasdaq markets as well. The portfolio contains approximately 2,000 stocks with average capitalization of $100 million.

这是书中对“large stocks”和“small stocks”的解释，并没有说到各占多少比例

Since 1982, this portfolio has included smaller stocks listed on the Amex and Nasdaq markets as well.

能把PORTFOLIO的情况说一下吗？

“Small Stocks”represents the value-weighted portfolio of the lowest-capitalization quintile (that is, the firms in the bottom 20% of all companies traded on the NYSE when ranked by market capitalization).

porfolio 就是上面那个红色的portfolio