cachemanager reports negative byte hit ratio?

From the cachemanager (cache_object://proxy/info):

Squid Object Cache: Version 2.1.PATCH2
Start Time: Mon, 22 Mar 1999 15:20:32 GMT
Current Time: Thu, 25 Mar 1999 12:49:02 GMT
Connection information for squid:
        Number of clients accessing cache: 0
        Number of HTTP requests received: 2209834
        Number of ICP messages received: 6801616
        Number of ICP messages sent: 7685835
        Number of queued ICP replies: 0
        Request failure ratio: 0.00%
        HTTP requests per minute: 530.1
        ICP messages per minute: 3475.4
        Select loop called: 44703630 times, 5.595 ms avg
Cache information for squid:
        Request Hit Ratios: 5min: 43.3%, 60min: 45.9%
        Byte Hit Ratios: 5min: -27.5%, 60min: 12.8%

How is the (negative) Byte Hit Ratio calculated? Also, the number of
clients is (wrongly) reported as zero. Has anybody else seen this?

Thanks,

--
Jan.Torreele@belnet.be, BELNET, the Belgian National Research Network