A ZFS scrub progressing, more than one hundred percent done

sh-3.2$ date
Mon 30 Sep 2013 23:11:11 BST
sh-3.2$ zpool status
  pool: gjp22
 state: ONLINE
 scan: scrub in progress since Sun Sep 29 20:48:19 2013
    495Gi scanned out of 494Gi at 5.51Mi/s, (scan is slow, no estimated time)
    0 repaired, 100.30% done
config:

	NAME                                         STATE     READ WRITE CKSUM
	gjp22                                        ONLINE       0     0     0
	  GPTE_71B8BDA2-3EBA-4B91-9E1C-2AE2B1DAAD06  ONLINE       0     0     0  at disk2s2
	cache
	  GPTE_4DE8B2ED-797A-407B-A11B-C51B96DBD4CB  OFFLINE      0     0     0

errors: No known data errors
sh-3.2$ uptime
23:12  up 1 day,  1:18, 7 users, load averages: 2.88 3.57 3.96
sh-3.2$ date
Mon 30 Sep 2013 23:14:06 BST
sh-3.2$ zpool status
  pool: gjp22
 state: ONLINE
 scan: scrub repaired 0 in 26h25m with 0 errors on Mon Sep 30 23:13:54 2013
config:

	NAME                                         STATE     READ WRITE CKSUM
	gjp22                                        ONLINE       0     0     0
	  GPTE_71B8BDA2-3EBA-4B91-9E1C-2AE2B1DAAD06  ONLINE       0     0     0  at disk2s2
	cache
	  GPTE_4DE8B2ED-797A-407B-A11B-C51B96DBD4CB  OFFLINE      0     0     0

errors: No known data errors
sh-3.2$ sudo kextstat | grep zfs
Password:
  130    1 0xffffff7f807a6000 0x19b000   0x19b000   com.getgreenbytes.filesystem.zfs (2012.09.23) <13 7 5 4 3 1>
  131    0 0xffffff7f80943000 0x6000     0x6000     com.getgreenbytes.driver.zfs (2012.09.14) <130 13 7 5 4 3 1>
sh-3.2$