rank city passengers ranking airline
rank
city
passengers
ranking
airline
number
address
number
number
list length
number address number number <c, text>
1 united states, los angeles 14749 4 alaska airlines
what is the average number of passengers in the united states ?
WP VBD-AUX DT JJ NN IN NNS IN DT NNP NNPS .
5537.5
select avg ( c3_number ) from w where c2_address = 'united states'