+.PP
+In addition to the fields of the peer's database record, the following
+additional keys are defined.
+.TP
+.B failures
+The number of failed pings in the current or most recent batch, in
+decimal.
+.TP
+.B last-ping
+The round-trip time of the most recent ping in milliseconds, in the form
+.IB nn.n ms\fR,
+or
+.B timeout
+if the most recent ping timed out,
+or
+.B \-
+if no pings have yet completed.
+.TP
+.B max-ping
+The maximum successful ping time so far in milliseconds, in the form
+.IB nn.n ms\fR,
+or
+.B \-
+if no pings have yet succeeded.
+.TP
+.B mean-ping
+The average successful ping time so far in milliseconds, in the form
+.IB nn.n ms\fR,
+or
+.B \-
+if no pings have yet succeeded.
+.TP
+.B min-ping
+The minimum successful ping time so far in milliseconds, in the form
+.IB nn.n ms\fR,
+or
+.B \-
+if no pings have yet succeeded.
+.TP
+.B n-lost
+The number of pings which have been declared timed out so far, in
+decimal.
+.TP
+.B n-ping
+The number of successful pings so far, in decimal.
+.TP
+.B sd-ping
+The standard deviation of ping times so far in milliseconds, in the form
+.IB nn.n ms\fR,
+or
+.B \-
+if no pings have yet succeeded.
+.TP
+.B state
+One of the strings:
+.B idle
+if the peer has responded to a ping recently, and we are waiting for the
+.B every
+delay before we try again; or
+.B check
+if we are currently waiting for a ping to return.