Task: Question Generation
Input (English): Passage: Northern Europe is home to a large bear population, with an estimated 2,500 (range 2,350-2,900) in Sweden, about 2,200 in Finland, about 700 in Estonia and 70 in Norway, totaling to nearly 5,000 individuals in the wild. Another large and relatively stable population of brown bears in Europe, consisting of 2,500-3,000 individuals, is the Dinaric-Pindos (Balkans) population, with contiguous distribution in northeast Italy, Slovenia, Croatia, Bosnia and Herzegovina, Serbia, Montenegro, Republic of Macedonia, Albania, Bulgaria and Greece. Brown bears inhabited the mountains of Austria until as recently as 2011, after a reintroduction effort failed and the species became extinct again. There is currently no effort to reintroduce the species into Austria. The entire alpine population of brown bears includes about 50 individuals, most of them living in the Adamello-Presanella Alps in Italy. Reintroduction of 10 Slovenian brown bears to the Trentino area in 1998 and 2002 produced occasional visitors to the South Tirol, the Swiss Geography of the Alpss, Bavaria and isolated sightings in the Geography of the Alpss. The small group of bears living in the Carinthian-Slovenian Alps is connected to the larger Dinaric-Pindos population.
Output (English): How many years was the time span where there was reintroduction of 10 Slovenian brown bears to the Trentino area?