Statistics:

The -statistics option displays some usage statistics, f.e.

kuznet@alisa:~ $ ip -s n ls 193.233.7.254
193.233.7.254 dev eth0 lladdr 00:00:0c:76:3f:85 ref 5 used 12/13/20 \
    nud reachable
kuznet@alisa:~ $

Here ref is the number of users of this entry and used is a triplet of time intervals in seconds separated by slashes. In this case they show that:

1. the entry was used 12 seconds ago.
2. the entry was confirmed 13 seconds ago.
3. the entry was updated 20 seconds ago.