I think Japanese normally use in formal context.
Example 1: Newspaper
http://www.yomiuri.co.jp/politics/ne...OYT1T00385.htm
the end of article there's "だ".
Example 2: Research article
"Strong Inference"
This article is written in "だ・である調". there's some "だ"s.
Example 3: Novel
http://www.aozora.gr.jp/cards/000035...237_20060.html
This one is little bit old (because of copyright I can't draw new one by URL) but I can find "だ"s in recent novels I have.