The sheer volume of attacks occurring during the 1980-1988 Tanker War between Iran and Iraq deserves its own page of analysis. In the chart below, you can see how the war progressed according to total number of attacks per month. During the first three years of the War, attacks on Gulf shipping remained relatively sparse, as both combatants were concentrated with campaigns on land. As the ground war began to stalemate in 1984, however, the number of attacks skyrocketed, as both sides attempted to undermine the others economy by attacking each others maritime trading partners in the Gulf. Although the number of attacks dropped off slightly in 1985, the resumed in full force in 1986, with 1987 being the single highest grossing year for naval conflicts in our entire database.
This next graph shows the breakdown of attacks per month between Iran and Iraq. As you can see, Iraq overshadowed Iran in terms of absolute attacks in 1984 and 1985. This was mainly because its air force was numerically and technologically superior to Iran's aging fleet of American F-4s, and thus was able to more consistently project power into the Northern Gulf. In 1986-1987, however, Iran began to achieve parity using a "guerrilla" strategy employing speedboats armed with Chinese Silkworm missiles and underwater minefields.