diff --git a/src/minizinc/instance.py b/src/minizinc/instance.py
index 9d903b8..7f23c02 100644
--- a/src/minizinc/instance.py
+++ b/src/minizinc/instance.py
@@ -1000,10 +1000,11 @@ def flat(
             output = self._driver._run(cmd, solver=self._solver)
 
         statistics: Dict[str, Any] = {}
-        matches = re.findall(rb"%%%mzn-stat:? (\w*)=([^\r\n]*)", output.stdout)
-        for m in matches:
-            set_stat(statistics, m[0].decode(), m[1].decode())
-
+        for obj in decode_json_stream(output.stdout):
+            if obj["type"] == "statistics":
+                statistics = {k: v for k, v in obj["statistics"].items()}
+                break
+        
         try:
             yield fzn, ozn, statistics
         finally: