sectors include tourism, fisheries, coffee, satellite ground stations, remote workers and digital nomads, academia, research and conferences, liquor, wines and beers, ship registry and sailing qualifications, traditional products, honey and honey bees, and its use as a film location. Growth sectors for import substitution include agriculture, timber, bricks, blocks, minerals and rocks, and bottled water. The tourist industry is heavily based on the promotion of Napoleon's imprisonment as well as nature activities such as scuba diving, swimming with whale sharks, whale watching, bird watching, marine tours, and hiking. A golf course also exists and sportfishing is possible. Several hotels, B&Bs, and self-catering apartments operate on the island. The arrival of tourists is linked to the Saint Helena Airport (and in the past, the arrival and departure schedule of the now-retired RMS St Helena). Saint Helena produces the most expensive coffee in the world. It also produces and exports Tungi Spirit, made from the fruit of the prickly or cactus pears, Opuntia ficus-indica ("Tungi" is the local Saint Helenian name for the plant), and coffee liqueur, gin, and rum in its local distillery. Due to the absence of parasites and disease in bees, beekeepers collect some of the purest honey in the world. Saint Helena has a small fishing industry, landing mostly tuna. The fishery is committed to one-by-one fishing and uses the motto "one pole, one line, one fish at a time". Some of Saint Helena's exported tuna has been served in restaurants in Cape Town. Like Ascension Island and Tristan da Cunha, Saint Helena is permitted to issue its own postage stamps, an enterprise that provides an income. Saint Helena also issues domains under .sh. Economic statistics Between 2009 and 2017, Saint Helena's HDI increased from 0.714 to 0.756; this placed Saint Helena in the 'high' category of human development, according to the classification used by the United Nations. Compared to other countries around the globe, Saint Helena's HDI ranking rose from 93rd (out of 190 countries ranked) to 83rd in the world—an improvement of ten places. The average (median) annual wage on Saint Helena in 2018/19 was an estimated £8,410. The median male wage was higher than the median female wage. The gap between the two grew in 2013/14, but narrowed in 2017–18, as male wages fell on average, and the median female wage level grew. This is probably due to the completion of the construction of the