diff --git a/bin/autojump b/bin/autojump
index f8fd5ef..cf3f6b7 100755
--- a/bin/autojump
+++ b/bin/autojump
@@ -34,7 +34,7 @@ import re
 import shutil
 from tempfile import NamedTemporaryFile
 
-VERSION = 'release-v21.4.6'
+VERSION = 'release-v21.5.0'
 MAX_KEYWEIGHT = 1000
 MAX_STORED_PATHS = 1000
 COMPLETION_SEPARATOR = '__'
@@ -83,22 +83,24 @@ class Database:
 
     def add(self, path, increment = 10):
         """
-        Increase wheight of existing paths or initialize new ones to 10.
+        Increase weight of existing paths or initialize new ones to 10.
         """
         if path not in self.data:
             self.data[path] = increment
         else:
             import math
-            self.data[path] = math.sqrt((self.data[path]**2)+(increment**2))
+            self.data[path] = math.sqrt((self.data[path]**2) + (increment**2))
         self.save()
 
-    def decrease(self, path, increment=10):
+    def decrease(self, path, increment = 15):
         """
-        Decrease wheight of existing path. Unknown ones are ignored.
+        Decrease weight of existing path. Unknown ones are ignored.
         """
         if path in self.data:
-            import math
-            self.data[path] = math.sqrt((self.data[path] ** 2) - (increment ** 2))
+            if self.data[path] < increment:
+                self.data[path] = 0
+            else:
+                self.data[path] -= increment
             self.save()
 
     def decay(self):
@@ -232,8 +234,8 @@ def options():
             help='directory to jump to')
     parser.add_argument('-a', '--add', '--increase', metavar='DIR',
             help='manually add path to database, or increase path weight for existing paths')
-    parser.add_argument('-d', '--decrease', metavar='DIR',
-            help='manually decrease path weight in the database')
+    parser.add_argument('-d', '--decrease', nargs='?', type=int, const=15, default=False,
+            help='manually decrease path weight in database')
     parser.add_argument('-b', '--bash', action="store_true", default=False,
             help='enclose directory quotes to prevent errors')
     parser.add_argument('--complete', action="store_true", default=False,
@@ -257,7 +259,8 @@ def options():
     if (ARGS.decrease):
         if(ARGS.decrease != os.path.expanduser("~")):
             db = Database(DB_FILE)
-            db.decrease(ARGS.decrease)
+            # FIXME: handle symlinks?
+            db.decrease(os.getcwd(), ARGS.decrease)
         return True
 
     if (ARGS.purge):