History of scuba diving the high number of recreational scuba accidents. this started with informal training and led to the creation of training and certification agencies. BS-AC was formed in 1953, CMAS in 1959, NAUI in 1960 and PADI in 1966. The sport of scuba diving had its roots among the multitude of small enthusiastic snorkelling and spearfishing clubs in the decades just before and after the Second World War. After the invention of the "aqualung" by Cousteau and Gagnan, the first commercially marketed underwater breathing apparatus became available for sale for sporting purposes in the late 1940s. In 1951, Jim Auxie Jr and
Death rates in the 20th century Death rates in the 20th century Death Rates in the 20th century is the ratio of deaths compared to the population around the world throughout the 20th century. When giving these ratios, they are most commonly expressed by number of deaths per 1,000 people per year. Many factors contribute to death rates such as cause of death, increasing the death rate, an aging population, which could increase and decrease the death rates by birth rates, and improvements in public health, decreasing the death rate. According to the CIA World Factbook, , the global crude death rate is 7.99 deaths/1,000 population.