Apexchart legend units only in percentile

I am at a loss on how to display the correct units (ppm) in the legend instead of percentile.
I have tried adding unit: “ppm” on very possible line within the YAML file but nothing seems to work. Documentation does meantion but not for legend.

type: custom:apexcharts-card
chart_type: radialBar
experimental:
  color_threshold: true
header:
  show: true
  floating: false
  title: Pollen-Tree
  show_states: true
  colorize_states: true
apex_config:
  stacked: true
  legend:
    show: true
    position: left
  plotOptions:
    radialBar:
      offsetY: -10
      startAngle: 0
      endAngle: 270
      hollow:
        margin: 5
        size: 20%
        background: transparent
        image: false
      dataLabels:
        name:
          show: false
        value:
          show: false
series:
  - entity: sensor.pollen_bomen
    type: column
    name: Tree
    show:
      in_header: true
      extremas: true
    float_precision: 1
    color_threshold:
      - value: 0
        color: green
        opacity: 0.3
      - value: 96
        color: orange
      - value: 208
        color: red
  - entity: sensor.pollen_berk
    type: column
    name: Berk
    show:
      in_header: true
      extremas: true
    float_precision: 1
    color_threshold:
      - value: 0
        color: green
        opacity: 0.3
      - value: 96
        color: orange
      - value: 208
        color: red
  - entity: sensor.pollen_cipres
    type: column
    name: Cipres
    show:
      in_header: true
      extremas: true
    float_precision: 1
    color_threshold:
      - value: 0
        color: green
        opacity: 0.3
      - value: 96
        color: orange
      - value: 208
        color: red
  - entity: sensor.pollen_eik
    type: column
    name: Eik
    show:
      in_header: true
      extremas: true
    float_precision: 1
    color_threshold:
      - value: 0
        color: green
        opacity: 0.3
      - value: 96
        color: orange
      - value: 208
        color: red
  - entity: sensor.pollen_els
    type: column
    name: Els
    show:
      in_header: true
      extremas: true
    float_precision: 1
    color_threshold:
      - value: 0
        color: green
        opacity: 0.3
      - value: 96
        color: orange
      - value: 208
        color: red
  - entity: sensor.pollen_hazelaar
    type: column
    name: Hazelaar
    show:
      in_header: true
      extremas: true
    float_precision: 1
    color_threshold:
      - value: 0
        color: green
        opacity: 0.3
      - value: 96
        color: orange
      - value: 208
        color: red
  - entity: sensor.pollen_iep
    type: column
    name: Iep
    show:
      in_header: true
      extremas: true
    float_precision: 1
    color_threshold:
      - value: 0
        color: green
        opacity: 0.3
      - value: 96
        color: orange
      - value: 208
        color: red
  - entity: sensor.pollen_pijnboom
    type: column
    name: Pijnboom
    show:
      in_header: true
      extremas: true
    float_precision: 1
    color_threshold:
      - value: 0
        color: green
        opacity: 0.3
      - value: 96
        color: orange
      - value: 208
        color: red
  - entity: sensor.pollen_plataan
    type: column
    name: Plataan
    show:
      in_header: true
      extremas: true
    float_precision: 1
    color_threshold:
      - value: 0
        color: green
        opacity: 0.3
      - value: 96
        color: orange
      - value: 208
        color: red
  - entity: sensor.pollen_populier
    type: column
    name: Populier
    show:
      in_header: true
      extremas: true
    float_precision: 1
    color_threshold:
      - value: 0
        color: green
        opacity: 0.3
      - value: 96
        color: orange
      - value: 208
        color: red