\begin{table}%T4
\caption{Diode cross-calibration data.} 
\label{table:4}      
%\centering
\par
\small                        
\begin{tabular}{lll }              
\hline \hline                              
  Diode D1 & Diode D2 & D1/D2 \\
  21.48 $\mu$A & 22.04 $\mu$A & 0.975 \\
  83.0 nA                  & 83.3 nA                & 0.998 \\
                          & Average ratio           & 0.986 \\  
\hline                                   
\end{tabular}
\end{table}