I'm trying to make an ENTIRE table gray (see picture

but I can't get it to work with \raisebox.
Here's my code:
\documentclass[a4paper,11pt]{article}
\usepackage{color,amsmath,amsfonts,amssymb}
\usepackage{rotating}
\usepackage{colortbl}
\definecolor{Gray}{gray}{0.9}
\newcolumntype{g}{>{\columncolor{Gray}}c}
\begin{table}[h]
\begin{center} {\footnotesize
\begin{tabular}{lccg}
\hline
& \multicolumn{3}{c}{AFC Window 1} \\
& \multicolumn{1}{c}{gmt} & \multicolumn{1}{c}{jfk} &
\multicolumn{1}{c}{fbi}\\\hline
\rowcolor{Gray}
& $0.025^*$ & -0.002 & $1.155^*$ \\[-2ex]
\rowcolor{Gray}
\raisebox{2ex}{Constant} & (1.22) & (2.22) & (0.56)\\[0ex]
& $0.025^*$ & -0.002 & $1.155^*$ \\[-2ex]
\raisebox{2ex}{Constant} & (1.22) & (2.22) & (0.56)\\[0ex]
& $0.025^*$ & -0.002 & $1.155^*$ \\[-2ex]
\raisebox{2ex}{Log(assets)$^a$} & (1.22) & (2.22) & (0.56)\\[0ex]
\hline
\end{tabular} }
\end{center}
\caption{\footnotesize Number of turns and distance between top and bottom.}
\label{turns}
\end{table}
\end{document}
Thanks guys.

