Complex sentence: In 1986, Lamy, Montblanc, and Parker held between them 70--80 percent of the West German market, and export markets then consisted of the US, Japan, and Austria.
Split into simpler sentences: In 1986, Lamy, Montblanc, and Parker held among them 70--80 percent of the West German market. Export markets then consisted of the US, Japan, and Austria.