diff --git a/statisticsFromHashes.py b/statisticsFromHashes.py
index 01c05ee..5dffbfd 100644
--- a/statisticsFromHashes.py
+++ b/statisticsFromHashes.py
@@ -7,10 +7,9 @@ os.chdir(path)
 def getDifficultyOfHash(hexHash):
     return int(hexHash, 16)
 
+difficultyRatios = {}
 X, Y = [], []
 
-difficultyRatios = []
-
 with open('hashes.txt') as f:
     lines = f.read().splitlines()
     for line in lines:
@@ -19,21 +18,14 @@ with open('hashes.txt') as f:
         target = lineParts[1]
         hashDifficulty = getDifficultyOfHash(hash)
         targetDifficulty = getDifficultyOfHash(target)
-        difficultyRatio = math.log2(targetDifficulty / hashDifficulty)
-        difficultyRatios += [difficultyRatio]
-
-i = 0
-for difficultyRatio in difficultyRatios:
-    if 1 < difficultyRatio and difficultyRatio < 2:
-        i += 1
-print(i)
-
-N = 100
-
-for i in range(N):
-    y = 0
-    for difficultyRatio in difficultyRatios:
+        # If use `round` instead of `int`, then it gives the same result as before.
+        difficultyRatio = round(math.log2(targetDifficulty / hashDifficulty))
+        if difficultyRatio in difficultyRatios:
+            difficultyRatios[difficultyRatio] += 1
+        else:
+            difficultyRatios[difficultyRatio] = 1
 
+for i in range(max(difficultyRatios) + 1):
     if i in difficultyRatios:
         X += [i]
         Y += [difficultyRatios[i] / len(lines)]