diff --git a/src/pdata/space_map.rs b/src/pdata/space_map.rs
index c55ebde..7c138bf 100644
--- a/src/pdata/space_map.rs
+++ b/src/pdata/space_map.rs
@@ -103,6 +103,7 @@ where
             if self.counts[b as usize] == V::from(0u8) {
                 self.counts[b as usize] = V::from(1u8);
                 self.first_free = b + 1;
+                self.nr_allocated += 1;
                 return Ok(Some(b));
             }
         }