Complex sentence: Agriculture in Germany is a small sector of the German economy, and it has declined in importance during the 20th century and by 1989 amounted to only 1.6 percent of the West German GDP.
Split into simpler sentences: Agriculture in Germany is a small sector of the German economy. It has declined in importance during the 20th century and by 1989 amounted to only 1.6 percent of the West German GDP.