diff --git a/src/models/pools.rs b/src/models/pools.rs
index d879f5b..4f32c13 100644
--- a/src/models/pools.rs
+++ b/src/models/pools.rs
@@ -49,7 +49,7 @@ pub struct StakePoolDelegators {
 #[derive(Deserialize)]
 pub struct StakePoolHistoryData {
     pub active_stake: i64,
-    pub active_stake_pct: String,
+    pub active_stake_pct: Option<String>,
     pub block_cnt: i64,
     pub deleg_rewards: i64,
     pub delegator_cnt: i64,