How to change bin width of a histogram

I'm attempting to draw a histogram of 8 bins of width 10. This is what I currently have, where my bin width is notably much less than 10 units.

    \begin{tikzpicture}
\begin{axis} [ybar,xmin=70,xmax=160,ymin=0,ymax=20, xlabel = IQ Scores, ylabel = Frequency, xtick={70, 80, 90, 100, 110, 120, 130, 140, 150}]
\addplot [draw = black, fill = gray] coordinates {
(75,2)
(85,3)
(95, 10)
(105, 16)
(115, 13)
(125, 10)
(135, 5)
(145,1)
};
\end{axis}
\end{tikzpicture}


I basically need the bars to touch each other. Any ideas what I need to do?

One way to do so is to use ybar interval (notice the slight difference in tick position in x axis)

\begin{tikzpicture}
\begin{axis} [ybar interval,
grid=none,
xmin=70,xmax=160,ymin=0,ymax=20, xlabel = IQ Scores, ylabel = Frequency, xtick={70, 80, 90, 100, 110, 120, 130, 140, 150}]
\addplot [draw = black, fill = gray] coordinates {
(75,2)
(85,3)
(95, 10)
(105, 16)
(115, 13)
(125, 10)
(135, 5)
(145,1)
(155,0)
};
\end{axis}
\end{tikzpicture}


You can set the unit width of the x-axis (e.g. x=0.1cm) and the bar width (bar width=1cm since your step size is 10).

\documentclass{article}

\usepackage{pgfplots}
\pgfplotsset{compat=1.18}

\begin{document}
\begin{tikzpicture}
\begin{axis} [
ybar,
x=0.1cm,
bar width=1cm,
xmin=70,
xmax=160,
ymin=0,
ymax=20,
xlabel=IQ Scores,
ylabel=Frequency,
xtick={70, 80, 90, 100, 110, 120, 130, 140, 150}
]
\addplot [draw = black, fill = gray] coordinates {
(75,2)
(85,3)
(95, 10)
(105, 16)
(115, 13)
(125, 10)
(135, 5)
(145,1)
};
\end{axis}
\end{tikzpicture}
\end{document}