Index: tol/stdlib/general/_constant.tol
===================================================================
--- tol/stdlib/general/_constant.tol	(revision 567228fa6df2c9cd6c6ea33f705a2460c340a050)
+++ tol/stdlib/general/_constant.tol	(revision b0613c44e30bfd8e1472d83eb9e9d9aec548a91f)
@@ -78,6 +78,7 @@
 TimeSet Semestral     = D(1)*(M(1)+M(7));
 TimeSet Anual         = D(1)*M(1);
-TimeSet Bianual       = Periodic(y1900,2,Anual);
-TimeSet Bianual1      = Periodic(y1901,2,Anual);
+TimeSet Bianual       = Periodic(y1900,2, Anual);
+TimeSet Bianual1      = Periodic(y1901,2, Anual);
+TimeSet Decanual      = Periodic(y1901,10,Anual);
 
 TimeSet Hourly        = Mi(0);
@@ -95,4 +96,5 @@
 TimeSet Biyearly      = Periodic(y1900,2,Anual);
 TimeSet Biyearly1     = Periodic(y1901,2,Anual);
+TimeSet Tenyearly     = Periodic(y1901,10,Anual);
 
 TimeSet PseudoMensual = Range(D(1),0,6)*WD(1);