The average age of companies in the past 100 years was around 60, and today, few companies reach the 20th anniversary. Still, there are those that have been operating for centuries.
According to the British portal Business Financing, the world's oldest, still functioning, company is the Japan-based construction company Kongo Gumi. It has been operating constantly for nearly 1,500 years.
The portal lists St. Peter Stifts Kulinarium restaurant in Salzburg, Austria, as the oldest company in Europe. The oldest companies in Europe are predominantly related to traditional products which reflect the nation's culture and which primarily have to do with food and drinks.
The oldest company in Serbia is Apatinska Pivara, founded in 1756. In Bosnia and Herzegovina it is Sarajevska Pivara, founded in 1864, in Croatia it is the Kraljevica Shipyard from 1729 and in Montenegro it is Posta Crne Gore, founded in 1841.
A detailed map can be found at this link