table text with subscript not fitting into the table width

Question

I have a table that has a 11 columns. I have one word in the top column with a subscript that seems to be going out of its box. is there any way to fix it?

i tried to use \tiny with the subscript, use tabularx and supertabular environments but nothing seems to be working yet. it still spills out of the cell.

\documentclass{article}
\usepackage{latexsym}

\begin{document}
\begin{table}[htbp]
\begin{scriptsize}
\begin{center}
\begin{tabular}{p{1.5cm}p{1cm}p{1cm}p{1cm}p{1cm}p{1cm}p{1cm}p{1cm}p{1cm}p{1cm}p{1cm}}
\hline
& 
(1)& (2)& (3)& (4)& (5)& (6)& (7)& (8)& (9)& (10) \\
\hline
 & 
\multicolumn{5}{|p{222pt}|}{\textbf{Historical stock market development from 1913 to 1960 [col. (1) to (5)]}} & 
\multicolumn{5}{|p{220pt}|}{\textbf{Recent stock market development from 1991 to 2007 [col. (6) to (10)]}} \\
\hline
Dep. Var. $=$ stock market capitalization to GDP (\textit{MCY})& 
Dep. Var. $= \quad \Delta $\textit{MCY}$_{1913-1960}$;$_{\, }\Delta $\textit{State} is from 51-1900 & 
Dep. Var. $= \quad \Delta $\textit{MCY}$_{1913-\, 1960}$;$_{\, }\Delta $\textit{State} is from 501-1900 & 
Dep. Var. $= \quad \Delta $\textit{MCY}$_{1913-\, 1960}$;$_{\, }\Delta $\textit{State} is from 1001-1900 & 
Dep. Var. $= \quad \Delta $\textit{MCY}$_{1913-\, 1960}$;$_{\, }\Delta $\textit{State} is from 1501-1900 & 
Dep. Var. $= \quad \Delta $\textit{MCY}$_{1913-\, 1960}$;$_{\, }\Delta $\textit{State} is from 1851-1900 & 
Dep. Var. $= \quad \Delta $\textit{MCY}$_{1991-2007}$;$_{\, }\Delta $\textit{State} is from 51-1950& 
Dep. Var. $= \quad \Delta $\textit{MCY}$_{1991-2007}$;$_{\, }\Delta $\textit{State} is from 501-1950& 
Dep. Var. $= \quad \Delta $\textit{MCY}$_{1991-2007}$;$_{\, }\Delta $\textit{State} is from 1001-1950& 
Dep. Var. $= \quad \Delta $\textit{MCY}$_{1991-2007}$;$_{\, }\Delta $\textit{State} is from 1501-1950& 
Dep. Var. $= \quad \Delta $\textit{MCY}$_{1991-2007}$;$_{\, }\Delta $\textit{State} is from 1901-1950 \\
\hline
$\Delta $\textit{State}& 
-0.223 \newline
 (-0.125)& 
3.178 \newline
(1.456)& 
5.650 \newline
(1.656)& & & & & & & &
\hline
\end{tabular}
\label{tab1}
\end{center}
\end{scriptsize}
\end{table}
\end{document}

Answer 1

I suggest to redesign your table in something like this:

Edit: AsMico pointed in his comment below,. the determination of \multicolumn with in the first version of answer with \newcommand\mcx[1]{\multicolumn{5}{>{\hsize=6\hsize}C}{\bfseries#1}} is bit mysterious ... The following changes of code (hopefully) is more consistent and also gives better result:

\newlength\lengthx % basic column width
\setlength{\lengthx}{\dimexpr0.091\textwidth-2\tabcolsep-1.25\arrayrulewidth\relax}
\newlength\lengtha % width of five-columm multicolumn
\setlength{\lengtha}{\dimexpr5\lengthx+10\tabcolsep+5\arrayrulewidth\relax}
\newcommand\mcx[1]{\multicolumn{5}{@{}>{\centering\arraybackslash}p{\lengtha}@{}}{\bfseries#1}}

In this change are defined two new lengths: \lengthx, which is the width of one column without tabcolsep and part of arrayrulewidth, and \lengtha which determine width of 5 columns. This, on the first sight complicated solution, is necessary that p{\lengtha} can exploit for its cell contents all available space of five C (or X) type columns.

Considering this changes, the table become

\documentclass{article}
\usepackage[margin=25mm]{geometry}

\usepackage{booktabs, multirow, tabularx}
\newcolumntype{C}{>{\centering\arraybackslash}X}
\newlength\lengthx % basic column width
\setlength{\lengthx}{\dimexpr0.091\textwidth-2\tabcolsep-1.25\arrayrulewidth\relax}
\newlength\lengtha % width of five-columm multicolumn
\setlength{\lengtha}{\dimexpr5\lengthx+10\tabcolsep+5\arrayrulewidth\relax}
\newcommand\mcx[1]{\multicolumn{5}{@{}>{\centering\arraybackslash}p{\lengtha}@{}}{\bfseries#1}}

\usepackage{showframe}% only for showing page layout, in the real application had to be removed
\renewcommand*\ShowFrameColor{\color{red}}

\begin{document}
    \begin{table}%[htbp]
\caption{Dep. Var. $=$ stock market capitalization to GDP (\textit{MCY})}
\label{tab1}
    \small
    \centering
\begin{tabularx}{\textwidth}{@{}X *{10}{C}@{}}
    \toprule
    & (1) & (2) & (3) & (4) & (5) & (6) & (7) & (8) & (9) & (10)    \\
    \cmidrule(r){2-6}\cmidrule(l){7-11}
    & \mcx{Historical stock market development from 1913 to 1960 [col. (1) to (5)]\newline\normalfont
    Dep. Var. $= \Delta \textit{MCY}_{1913-1960}$;%\newline
    $_{\, }\Delta $\textit{State} is from years:}
        & \mcx{Recent stock market development from 1991 to 2007 [col. (6) to (10)] \newline\normalfont
        Dep. Var. $= \Delta $\textit{MCY}$_{1991-2007}$;%\newline
        $_{\, }\Delta $\textit{State} is from years:} \\
    \cmidrule(r){2-6}\cmidrule(l){7-11}
    & 51   -- 1900 
    & 501  -- 1900 
    & 1001 -- 1900 
    & 1501 -- 1900 
    & 1851 -- 1900 
    & 51   -- 1950
    & 501  -- 1950
%
    & 1001 -- 1950
    & 1501 -- 1950
    & 1901 -- 1950 \\
    \midrule
\multirow{2}*{$\Delta$ \textit{State}}
    &   ~~$-0.223$ $(-0.125)$
    &   3.178  (1.456)
    &   5.650  (1.656)
    & & & & & & &   \\ 
    \bottomrule
\end{tabularx}
    \end{table}
\end{document}