There are no current official estimates of the amount of trash dumped in the ocean every year, but a study conducted in 1975 by the National Academy of Science estimated that 14 billion pounds of trash went in every year.
Much has changed in the World since 1975, most notably the 1988 ratification of MARPOL 73/78 Annex V, the international convention limiting ships from dumping trash, which has served to reduce the amount of trash released by the shipping industry.
On the other hand, the global population has almost doubled since 1975 – in fact, the number of people currently living within 120 miles of a coastline is the same number as we as were living on the whole planet in 1975. Population estimates show that around 3.5 billion people live in or near coastal communities.
The 2010 United States Census population map shows that some of the highest population densities exist along coastal areas.