Iparitól a Jelenkorig

Era	Industrial Age	Progressive Era	Modern Era	Postmodern Era	Contemporary Era
Tower
1.	500	750	1100	1500	2000
2.	300	500	750	1000	1500
3.	200	300	500	750	1000
4.	100	200	300	500	750
5.	80	100	200	300	500
6.	60	80	100	200	300
7.	50	60	80	100	200
8.	40	50	60	80	100
9.	20	40	50	60	80
10.	10	20	40	50	60

Return Bronze to Colonial Age Tomorrow to Arctic Future Era