diff --git a/tig-benchmarker/common/structs.py b/tig-benchmarker/common/structs.py
index c746f3d..c2d29f1 100644
--- a/tig-benchmarker/common/structs.py
+++ b/tig-benchmarker/common/structs.py
@@ -161,8 +161,8 @@ class BlockDetails(FromDict):
 
 @dataclass
 class BlockData(FromDict):
-    confirmed_ids: Dict[str, Set[int]]
-    active_ids: Dict[str, Set[int]]
+    confirmed_ids: Dict[str, Set[str]]
+    active_ids: Dict[str, Set[str]]
 
 @dataclass
 class Block(FromDict):