diff --git a/README.md b/README.md
index 1d93a85d527554e37dae4865e88e0614bc2f6661..8fbb1b2596317a0d2758153bfc681ce27dde4f78 100644
--- a/README.md
+++ b/README.md
@@ -63,7 +63,7 @@ To display all available options, type:
 
     python plot_gender.py -h
 
-For example, we can statistically show that the prison-punishment was "invented" in 19th century.
+For example, we can statistically show that the prison-punishment was "invented" in 18th/19th century.
 
     python plot_gender.py imprison