The sisal industry is the oldest commercially organised agricultural undertaking and one of the longest surviving agricultural industries in Tanzania. Introduced in 1893 by Dr. Richard Hindorf a German Agronomist, as a commercial crop, the sisal industry grew to become the most extensive commercial agriculture and primary processing in Central Africa, spreading to Kenya, Mozambique and Angola. Peak production was reached in 1964 when Tanzania alone produced 234,000 tons grown in Tanga, Morogoro, Coast, Kilimanjaro, Arusha, Singida, Iringa, Mwanza, Shinyanga, Mara, Mtwara and Lindi regions, virtually throughout Tanzania. Sisal has played a significant role in the country's economy being the largest foreign exchange earner in Tanzania up to the 70's and the largest employer providing employment to over 1,000,000 permanent and casual workers. It is expected to continue as it still provides a well being for 350,000 people in the country.