Facts and addiction level of Marijuana... Please?

Ok.. So my Drivers Ed teacher told me that Marijuana was the 2nd most addicting drug next to Heroin... When you answer please actually have information from legitimate sources and cite them.

I really wanna prove this dude wrong because he's like 68 years old and is a DOOOOOOOSH!

: http://alcoholdrugstreatment.info/facts-and-addiction-level-of-marijuana-please