Exponential trendline to best fit I-V curve data

Question

I am trying to plot a best-fit trendline to an I-V curve for a Zener diode. The data is exponential so linear regression is not suitable in this instance.

Here is my data. The important columns are 2 and 3, which are current and voltage, respectively. In this case, the current data is being plotted as a function of voltage.

column 1,column 2,column 3

-15.0,-13.33,-0.71

-11.2,-9.71,-0.696

-7.50,-6.30,-0.675

-3.76,-3.45,-0.636

0,0,0

3.76,3.00,0.639

7.51,6.56,0.676

11.2,10.16,0.696

15,13.7,0.71

Here is part of the code I am working with:

\documentclass{article}
\usepackage{tikz, pgfplots, pgfplotstable, siunitx}

\usepgfplotslibrary{units}

\sisetup{
  round-mode = places,
  round-precision = 2,
}

\begin{document}

  \begin{figure}[h!]
    \begin{center}
    \begin{tikzpicture}
      \begin{axis}[
          width=\linewidth,
          grid=major, 
          grid style={dashed,gray!30},
          xlabel=Voltage, 
          ylabel=Current,
          x unit=\si{\volt}, 
          y unit=\si{\milli\ampere},
          legend style={at={(0.5,1.4)},anchor=north},
          x tick label style={rotate=90,anchor=east}
        ] 
        \addplot [only marks, mark = *, blue] table[x=column 3,y=column 2,col sep=comma]{tables/Table 6.csv};
        \addlegendentry{$y(x)$}
      \end{axis}
    \end{tikzpicture}
    \caption{Zener diode reverse bias}
  \end{center}
  \end{figure}

\end{document}