M = [24 80; 24 80; 24 80; 24 80; 30 120; 30 120; 48 124; 48 124; 48 124];
[c,g] = groupcounts(M(:,2))
There are your y- and x-axis numbers.
Perhaps one of these plots is what you mean:
x = 1:numel(g);
figure('Position',[10 10 1000 400])
tiledlayout(2,2)
nexttile
plot(g,c)
nexttile
bar(g,c)
nexttile
plot(x,c)
xticks(x)
xticklabels(g)
nexttile
bar(x,c)
xticks(x)
xticklabels(g)
