Problem with barometerRate WeeWX

[Remy Lavabre]

Hello,

I have a problem with using the barometerRate variable.

In skin :

<td class="label">$obs.label.barometerRate</td>

<td class="data">$current.barometerRate</td>

And the result in HTML is :

Barometer Change Rate ?'barometerRate'?

I don't understand why the "$current.barometerRate" variable is not reconize....

Where is the problem ? (Weewx 4.5.1)

Thank-you...