diff --git a/collocatordb.h b/collocatordb.h
index 70c6c11..dae2047 100644
--- a/collocatordb.h
+++ b/collocatordb.h
@@ -15,6 +15,7 @@
     class Collocator {
     public:
     uint64_t w2;
+    uint64_t f2;
     uint64_t raw;
     double pmi;
     double npmi;