This becomes a bit more complicated with multiple lines.
This assumes you want the gray region between the maximum and minimum line values —
x = linspace(0, 5, 10).';; % Assume Column Vectors
y = ([0.5 0.75 0.9 0.95 1.1] + x*(1:5))*1E+6;
figure
plot(x, y) % Plot Lines
hold on
patch([x; flip(x)], [min(y,[],2); flip(max(y,[],2))], [1 1 1]*0.5, 'FaceAlpha', 0.25) % Plot Gray 'patch'. Set 'FaceAlpha' (Transparency) To Show Lines
hold off
xlabel('Jahr')
ylabel('BoddenVolume in m^3')
lgdstr = compose('Limit 0.01 Cutoff %3d',[95 98 99 100]);
legend('PIZ', lgdstr{:}, 'Location','best')
.
