diff --git a/CHANGELOG.md b/CHANGELOG.md
index ffa68d0..9f93351 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,4 +1,5 @@
 # Changelog
 
-## [1.9-SNAPSHOT] - 2020-11-25
+## [1.9-SNAPSHOT] - 2021-09-15
 - for `.*\\.(freq|tsv)(\\.gz)?` input files automatically cumulate frequencies
+- -N option added to sort keys with same frequency numerically
\ No newline at end of file
diff --git a/src/main/java/org/ids_mannheim/TotalNGrams.java b/src/main/java/org/ids_mannheim/TotalNGrams.java
index 952998a..86932d4 100644
--- a/src/main/java/org/ids_mannheim/TotalNGrams.java
+++ b/src/main/java/org/ids_mannheim/TotalNGrams.java
@@ -2,13 +2,13 @@
 
 import org.anarres.parallelgzip.ParallelGZIPOutputStream;
 import org.apache.commons.compress.compressors.xz.XZCompressorOutputStream;
-import org.tukaani.xz.XZOutputStream;
 import picocli.CommandLine;
 
 import java.io.BufferedOutputStream;
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.PrintStream;
+import java.math.BigInteger;
 import java.util.ArrayList;
 import java.util.Locale;
 import java.util.concurrent.*;
@@ -87,6 +87,11 @@
             "--sort"}, description = "Toggle output sorting (default: ${DEFAULT-VALUE})")
     boolean sort = true;
 
+    @SuppressWarnings("CanBeFinal")
+    @CommandLine.Option(names = {"-N",
+            "--numeric-secondary-sort"}, description = "Sort entries with same frequency numerically  (default: ${DEFAULT-VALUE})")
+    boolean numericSecondarySort = false;
+
     private Progressbar etaPrinter;
 
     public TotalNGrams() {
@@ -187,7 +192,10 @@
                         if (cmp1 != 0) {
                             return cmp1;
                         } else {
-                            return a.getKey().compareTo(b.getKey());
+                            if (numericSecondarySort)
+                                return new BigInteger(a.getKey()).compareTo(new BigInteger(b.getKey()));
+                            else
+                                return a.getKey().compareTo(b.getKey());
                         }
                     })
                     .forEachOrdered(entry -> output_stream.println(entry.getKey() + "\t" + Integer.toUnsignedString(entry.getValue().get())));