diff --git a/include/Kyoto/TAverage.hpp b/include/Kyoto/TAverage.hpp
index 71f92258..5d36d0b2 100644
--- a/include/Kyoto/TAverage.hpp
+++ b/include/Kyoto/TAverage.hpp
@@ -11,13 +11,7 @@ class TAverage : rstl::vector< T > {
 public:
   TAverage() {}
   TAverage(int capacity, const T& value);
-  void AddValue(const T& value) {
-    push_back(value);
-    for (int i = size() - 1; i > 0; --i) {
-      operator[](i) = operator[](i - 1);
-    }
-    operator[](0) = value;
-  }
+  void AddValue(const T& value);
   rstl::optional_object< T > GetAverage() const;
 };
 
@@ -26,4 +20,13 @@ TAverage< T >::TAverage(int capacity, const T& value) {
   resize(capacity, value);
 }
 
+template < typename T >
+void TAverage< T >::AddValue(const T& value) {
+  push_back(value);
+  for (int i = size() - 1; i > 0; --i) {
+    operator[](i) = operator[](i - 1);
+  }
+  operator[](0) = value;
+}
+
 #endif