Round number on Statistics Card

Hi there,
I have a Statistics Card with a sensor that stores long-term statistics. Now I would like to round the displayed number without any decimals (see image), but cannot figure out how to do it.

It is a total increasing sensor and the absolute value is rounded but not the statistically calculated one.

Here is my yaml card code:

type: vertical-stack
cards:
  - type: horizontal-stack
    cards:
      - type: statistic
        period:
          calendar:
            period: year
        stat_type: change
        entity: sensor.gaszaehler_value
        name: Jahresverbrauch
        icon: mdi:chart-bar
        theme: Bubble
        footer:
          type: picture
          image: /local/gasheizung.png

Does someone have an idea how to reach my goal?