Here’s a nice easy way I found:
h <- hist(g, breaks = 10, density = 10,
col = "lightgray", xlab = "Accuracy", main = "Overall")
xfit <- seq(min(g), max(g), length = 40)
yfit <- dnorm(xfit, mean = mean(g), sd = sd(g))
yfit <- yfit * diff(h$mids[1:2]) * length(g)
lines(xfit, yfit, col = "black", lwd = 2)