diff --git a/lib/ethosu_profiler/include/ethosu_profiler.hpp b/lib/ethosu_profiler/include/ethosu_profiler.hpp
index 503ebba..12c337c 100644
--- a/lib/ethosu_profiler/include/ethosu_profiler.hpp
+++ b/lib/ethosu_profiler/include/ethosu_profiler.hpp
@@ -39,8 +39,7 @@
     std::unique_ptr<const char *[]> tags_;
     std::unique_ptr<uint64_t[]> start_ticks_;
     std::unique_ptr<uint64_t[]> end_ticks_;
-
-    int num_events_ = 0;
+    size_t num_events_;
 
     TF_LITE_REMOVE_VIRTUAL_DELETE;
 };