Country | Product | Sales Volume |

France | Shoes | 10 |

France | Shoes | 20 |

France | Shoes | 30 |

France | Boots | 5 |

France | Boots | 5 |

France | Hat | 10 |

France | Hat | 5 |

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I want to create a measure that will return the number of products with a total sales volume of less than 20 (i.e. the result would be "2" from the above data, as "Boots" and "Hats" have sales volumes of 10 and 15 respectively.

Any help with creating the measure would be much appreciated. Thanks in advance!

Ben