XPATH - Values out of this xml file (Datex 2)

I’m trying to get values out of this xml file (https://data.public.lu/fr/datasets/r/07e6ff2e-040f-4b91-98e2-7d469b5e34b1), but it seems not to be easy. On the internet i found similar problems, but a solution for my problem, I couldn’t find.
I created a rule, where I use the http binding an the xpath transformation. Both bindings are installed on my system. In this example I was trying to get out the value of percentage.
Can someone help me?

rule "xml data"
        Time cron "0/10 * * ? * * *"
    val String longurl = sendHttpGetRequest("https://data.public.lu/fr/datasets/r/07e6ff2e-040f-4b91-98e2-7d469b5e34b1")
    val String percentage = transform("XPATH", "/d2LogicalModel/payloadPublication/siteMeasurements[7]/measuredValue[2]/measuredValue/basicData/occupancy/percentage/text()", longurl)
    logInfo("xml data", "percentage: " + percentage)

best regards