I would like to know the number of restraunt servers whose income
relies on  tips recived in the US.
The number of people in support roles ( barbacks, bartenders
busboys/server assistants/)
And the number of valets, doormen and bellmen who rely on tips for their income. 
I also would like to know the average hourly wage that a tipped
employee in each of these professions recieves in the US.
 And the average %tip recieved 
Please use statistics no earlier than 2000 and I would appreciate the
most curent statistics possible. Please include this information in
your ansewers as well as the refence that you used.
Thank you