image/svg+xml
P
R
D
E
1. Kondratiev
2. Kondratiev
3. Kondratiev
4. Kondratiev
5. Kon...
steam enginecotton
railwaysteel
electrical engineeringchemistry
petrochemicalsautomobiles
information technology
1800
1850
1900
1950
1990
P: prosperity
R: recession
D: depression
E: improvement