most people have a blood sugar level of 72 milligrams to 144 milligrams per deciliter -lrb- 4 to 8 millimoles per liter -rrb- , but it is quite common for diabetics to have a blood sugar level of 180 milligrams to 360 milligrams per deciliter -lrb- 10 to 20 millimoles per liter -rrb- , watkins said .