Please answer a question about the following article about Eritrea:

Lions are said to inhabit the mountains of the Gash-Barka Region. There is also a small population of elephants that roam in some parts of the country. Dik-diks can also be found in many areas. The endangered African wild ass can be seen in Denakalia Region. Other local wildlife include bushbucks, duikers, greater kudus, klipspringers, African leopards, oryxs and crocodiles., The spotted hyena is widespread and fairly common. Between 1955 and 2001 there were no reported sightings of elephant herds, and they are thought to have fallen victim to the war of independence. In December 2001 a herd of about 30, including 10 juveniles, was observed in the vicinity of the Gash River. The elephants seemed to have formed a symbiotic relationship with olive baboons, with the baboons using the water holes dug by the elephants, while the elephants use the tree-top baboons as an early warning system.

In December 2001, how many elephants were seen in the vicinity of the Gash River?
about 30