diff --git a/src/blockchain.ts b/src/blockchain.ts
index c1ce774..91ae1f5 100644
--- a/src/blockchain.ts
+++ b/src/blockchain.ts
@@ -34,14 +34,18 @@ const blockGasPricesObservable = new Observable<GasPrices>((observer) => {
 const averageGasPricesObservable = blockGasPricesObservable.pipe(
   scan((acc, curr) => [...acc.slice(-19), curr], [] as GasPrices[]),
   map((blocks) => {
-    const fastSum = blocks.reduce((sum, block) => sum + block.fast, 0);
-    const averageSum = blocks.reduce((sum, block) => sum + block.average, 0);
-    const slowSum = blocks.reduce((sum, block) => sum + block.slow, 0);
+    const { fast, average, slow } = blocks
+      .reduce((sum, block) =>
+        ({ 
+          fast: sum.fast + block.fast,
+          average: sum.average + block.average,
+          slow: sum.slow + block.slow
+        }), { fast: 0, average: 0, slow: 0 } as GasPrices);
     return {
-      fast: Math.round(fastSum / blocks.length),
-      average: Math.round(averageSum / blocks.length),
-      slow: Math.round(slowSum / blocks.length),
-    };
+      fast: Math.round(fast / blocks.length),
+      average: Math.round(average / blocks.length),
+      slow: Math.round(slow / blocks.length),
+    } as GasPrices;
   })
 );