diff --git a/Package.resolved b/Package.resolved
index 27daaabac3..888ca3b156 100644
--- a/Package.resolved
+++ b/Package.resolved
@@ -6,8 +6,8 @@
         "repositoryURL": "https://github.com/apple/swift-algorithms",
         "state": {
           "branch": null,
-          "revision": "bb3bafeca0e164ece3403a9de646b7d38c07dd49",
-          "version": "0.0.2"
+          "revision": "b14b7f4c528c942f121c8b860b9410b2bf57825e",
+          "version": "1.0.0"
         }
       },
       {
@@ -15,8 +15,8 @@
         "repositoryURL": "https://github.com/apple/swift-numerics",
         "state": {
           "branch": null,
-          "revision": "6b24333510e9044cf4716a07bed65eeed6bc6393",
-          "version": "0.0.8"
+          "revision": "0a5bc04095a675662cf24757cc0640aa2204253b",
+          "version": "1.0.2"
         }
       }
     ]
diff --git a/Source/Charts/Data/Implementations/Standard/ChartDataSet.swift b/Source/Charts/Data/Implementations/Standard/ChartDataSet.swift
index 70d2da5582..440a737882 100644
--- a/Source/Charts/Data/Implementations/Standard/ChartDataSet.swift
+++ b/Source/Charts/Data/Implementations/Standard/ChartDataSet.swift
@@ -217,7 +217,7 @@ open class ChartDataSet: ChartBaseDataSet
         rounding: ChartDataSetRounding) -> Int
     {
         var closest = partitioningIndex { $0.x >= xValue }
-        guard closest < endIndex else { return rounding == .closest ? (endIndex-1) : -1 }
+        guard closest < endIndex else { return index(before: endIndex) }
 
         var closestXValue = self[closest].x
 
@@ -240,10 +240,13 @@ open class ChartDataSet: ChartBaseDataSet
             // The closest value in the beginning of this function
             // `var closest = partitioningIndex { $0.x >= xValue }`
             // doesn't guarantee closest rounding method
-            if closest > 0 {
+            if closest > startIndex {
                 let distanceAfter = abs(self[closest].x - xValue)
-                let distanceBefore = abs(self[closest-1].x - xValue)
-                distanceBefore < distanceAfter ? closest -= 1 : ()
+                let distanceBefore = abs(self[index(before: closest)].x - xValue)
+                if distanceBefore < distanceAfter
+                {
+                    closest = index(before: closest)
+                }
                 closestXValue = self[closest].x
             }
         }