How can I create the following table in LaTeX? I created the table below using PowerPoint.

Here is my best attempt at using LaTeX to create the table:
\begin{tabular}{l|l|l|}
\cline{2-3}
& \multicolumn{2}{|c|}{Returning Week} \\ \cline{2-3}
& 1 & 2 \\ \hline
\multicolumn{1}{|l|}{1} & 0.3 & 0.2 \\ \hline
\multicolumn{1}{|l|}{2} & 0.1 & 0.1 \\ \hline
\end{tabular}
and the output

Similar tex.stackexchange posts:
- Sideways label for table with alternating row colours includes a more extensive example of a table that includes this feature, but it is hard to parse because it includes many other features.
- How to make table with rotated table headers in LaTeX likewise has a table with many many entries, so is hard to parse as well



rotatingpackage and itssidewaysenvironment. Please add your code for the table (without the rotated label, of course). – karlkoeller Aug 22 '13 at 16:53