...Established in 1960, the royalty payments to ILA workers are based on the tons of container cargo that move through a port. That tonnage has risen from 50 million tons in 1996 to 110 million last year, according to the alliance. Total payments last year were $211 million, according to the USMX, or an average of $15,500 per worker.
The original idea of the royalty payments was to protect longshoremen from wage losses expected as a result of "containerization," in which more and more goods are packed in the now-familiar 20- and 40-foot long boxes. Those take less manpower to off-load than the less-standardized containers they replaced.
http://www.reuters.com/article/2012/12/28/us-usa-ports-deal-idUSBRE8BR0ET20121228
