How Dangerous is Marijuana?

Here is a compilation of annual causes of death according to the CDC:
Homicides: 16,121 (11,208 involved firearms (many were domestic abuse))
Alcohol-impaired driving crashes: 10,322 (1,168 were children 0-14 years old)
Heart disease: 611,105
Cancer: 584,881
Chronic lower respiratory diseases: 149,205
Accidents (unintentional injuries): 130,557
Stroke (cerebrovascular diseases): 128,978
Alzheimer's disease: 84,767
Diabetes: 75,578
Influenza and Pneumonia: 56,979
Nephritis, nephrotic syndrome, and nephrosis: 47,112
Intentional self-harm (suicide): 41,149
Marijuana: 0, no recorded cases of overdose deaths from cannabis have been found

Why is it illegal?  It can't be taxed other than by collecting money from arrests, tickets, court fees, fines and incarceration.  It is in the interest of the pharmaceutical industry, tobacco and alcohol industry, lumber industry and prison industry to keep it illegal.

For further reading, take a look at the LaGuardia Report on Marijuana:
http://www.druglibrary.org/schaffer/library/studies/lag/lagmenu.htm