Question: Which industry is a key element of Greek economic activity?
About the article "Greece", section "Maritime industry".

Candidate passages:
Greece is a maritime nation by tradition, as shipping is arguably the oldest form of occupation of the Greeks and has been a key element of Greek economic activity since ancient times. 
The shipping industry is a key element of Greek economic activity dating back to ancient times.
Today, shipping is one of the country's most important industries.
It accounts for 4.5% of GDP, employs about 160,000 people (4% of the workforce), and represents 1/3 of the country's trade deficit.
During the 1960s, the size of the Greek fleet nearly doubled, primarily through the investment undertaken by the shipping magnates, Aristotle Onassis and Stavros Niarchos.
The basis of the modern Greek maritime industry was formed after World War II when Greek shipping businessmen were able to amass surplus ships sold to them by the U.S. government through the Ship Sales Act of the 1940s.
According to a United Nations Conference on Trade and Development report in 2011, the Greek merchant navy is the largest in the world at 16.2% of the world's total capacity, up from 15.96% in 2010.
This is a drop from the equivalent number in 2006, which was 18.2%.
The total tonnage of the country's merchant fleet is 202 million dwt, ranked 1st in the world.
In terms of total number of ships, the Greek Merchant Navy stands at 4th worldwide, with 3,150 ships (741 of which are registered in Greece whereas the rest 2,409 in other ports).
In terms of ship categories, Greece ranks first in both tankers and dry bulk carriers, fourth in the number of containers, and fifth in other ships.
However, today's fleet roster is smaller than an all-time high of 5,000 ships in the late 1970s.
Additionally, the total number of ships flying a Greek flag (includes non-Greek fleets) is 1,517, or 5.3% of the world's dwt (ranked 5th).
The Hellenic Merchant Marine refers to the Merchant Marine of Greece, engaged in commerce and transportation of goods and services universally.
It consists of the merchant vessels owned by Greek civilians, flying either the Greek flag or a flag of convenience.
Greece is a maritime nation by tradition, as shipping is arguably the oldest form of occupation of the Greeks and a key element of Greek economic activity since the ancient times.
Nowadays, Greece has the largest merchant fleet in the world, which is the second largest contributor to the national economy after tourism and forms the backbone of world shipping.
The Greek fleet flies a variety of flags, however some Greek shipowners gradually return to Greece following the changes to the legislative framework governing their operations and the improvement of infrastructure. 
20th century.
During the 19th century slowly developing industrial activity (including heavy industry like shipbuilding) was mainly concentrated in Ermoupolis and Piraeus.
The series of wars between 1912 and 1922 provided a catalyst for Greek industry, with a number of industries such as textiles; ammunition and boot-making springing up to supply the military.
After the wars most of these industries were converted to civilian uses.
Greek refugees from Asia Minor, the most famous of which is Aristotle Onassis who hailed from Smyrna (modern Izmir) also had a tremendous impact on the evolution of Greek industry and banking.
Greeks held 45% of the capital in the Ottoman Empire before 1914, and many of the refugees expelled from Turkey had funds and skills which they quickly put to use in Greece.
These refugees from Asia Minor also led to rapid growth of urban areas in Greece, as the vast majority of them settled in urban centers such as Athens and Thessaloniki.
The 1920 census reported that 36.3% of Greeks lived in urban or semi-urban areas, while the 1928 census reported that 45.6% of Greeks lived in urban or semi-urban areas.
It has been argued by many Greek economists that these refugees kept Greek industry competitive during the 1920s, as the surplus of labor kept real wages very low.
Although this thesis makes economic sense, it is sheer speculation as there is no reliable data on wages and prices in Greece during this period.
Greek industry went into decline slightly before the country joined the EC, and this trend continued.
Although worker productivity rose significantly in Greece, labor costs increased too fast for the Greek manufacturing industry to remain competitive in Europe.
There was also very little modernization in Greek industries due to a lack of financing. 
The chief economic activity is light industry.