// Use Morris.Area instead of Morris.Line
Morris.Area({
element: 'graph',
behaveLikeLine: true,
data: [
{x: '2011 Q1', y: 3, z: 3},
{x: '2011 Q2', y: 2, z: 1},
{x: '2011 Q3', y: 2, z: 4},
{x: '2011 Q4', y: 3, z: 3}
],
xkey: 'x',
ykeys: ['y', 'z'],
labels: ['Y', 'Z']
});