S&P 500 (^GSPC)
Date	Open	High	Low	Close	Adj Close	Volume
12/1/15	2082.92993	2104.27002	1993.26001	2043.93994	2043.93994	83649260000
1/1/16	2038.19995	2038.19995	1812.29004	1940.23999	1940.23999	92409770000
2/1/16	1936.93994	1962.95996	1810.09998	1932.22998	1932.22998	93049560000
3/1/16	1937.08997	2072.20996	1937.08997	2059.73999	2059.73999	92639420000
4/1/16	2056.62012	2111.05005	2033.80005	2065.30005	2065.30005	81124990000
5/1/16	2067.16992	2103.47998	2025.91003	2096.94995	2096.94995	78883600000
6/1/16	2093.93994	2120.55005	1991.68005	2098.86011	2098.86011	86852700000
7/1/16	2099.34009	2177.09009	2074.02002	2173.6001	2173.6001	69530250000
8/1/16	2173.1499	2193.81006	2147.58008	2170.94995	2170.94995	75610310000
9/1/16	2171.33008	2187.87012	2119.12012	2168.27002	2168.27002	77270240000
10/1/16	2164.33008	2169.6001	2114.71997	2126.1499	2126.1499	73196630000
11/1/16	2128.67993	2214.1001	2083.79004	2198.81006	2198.81006	88299760000
12/1/16	2200.16992	2277.53003	2187.43994	2238.83008	2238.83008	75251240000

For each of the stock indices and stock, convert the price series into rates of return series.