```ruby
# frozen_string_literal: true

module Api
  module V3
    class AreaPresenter
      # These attributes will be kept as part of the JSON representation of the
      # area when the user does not request all attributes (detailed=false).
      SPARSE_ATTRIBUTES = Set.new(%w[
        analysis_year
        area
        base_dataset
        derived
        geo_id
        group
        number_of_inhabitants
        scaling
        useable
      ]).freeze

      # Attributes beginning with these substrings will also be included when
      # detailed=false.
      SPARSE_PREFIXES = %w[has_ use_].freeze

      # Creates a new Area API presenter.
      #
      # area - The Api::Area to be presented as JSON
      def initialize(area, detailed: false)
        @resource = area
        @detailed = detailed
      end

      # Creates a Hash of the Area data suitable for conversion to JSON by
      # Rails.
      #
      # Returns a Hash.
      def as_json(*)
        data = @resource.as_json

        # For compatibility with ETModel, which expects a "useable"
        # attribute which tells it if the region may be chosen.
        data['useable'] = data['enabled']['etmodel']
        data.delete('enabled')

        strip_unwanted(data)
      end

      private

      def strip_unwanted(attributes)
        return attributes if @detailed

        attributes.select do |key, _|
          SPARSE_PREFIXES.any? { |prefix| key.start_with?(prefix) } ||
            SPARSE_ATTRIBUTES.include?(key)
        end
      end
    end
  end
end
```

Include number_of_residences with sparse area data
user
```ruby
# frozen_string_literal: true

module Api
  module V3
    class AreaPresenter
      # These attributes will be kept as part of the JSON representation of the
      # area when the user does not request all attributes (detailed=false).
      SPARSE_ATTRIBUTES = Set.new(%w[
        analysis_year
        area
        base_dataset
        derived
        geo_id
        group
        number_of_inhabitants
        number_of_residences
        scaling
        useable
      ]).freeze

      # Attributes beginning with these substrings will also be included when
      # detailed=false.
      SPARSE_PREFIXES = %w[has_ use_].freeze

      # Creates a new Area API presenter.
      #
      # area - The Api::Area to be presented as JSON
      def initialize(area, detailed: false)
        @resource = area
        @detailed = detailed
      end

      # Creates a Hash of the Area data suitable for conversion to JSON by
      # Rails.
      #
      # Returns a Hash.
      def as_json(*)
        data = @resource.as_json

        # For compatibility with ETModel, which expects a "useable"
        # attribute which tells it if the region may be chosen.
        data['useable'] = data['enabled']['etmodel']
        data.delete('enabled')

        strip_unwanted(data)
      end

      private

      def strip_unwanted(attributes)
        return attributes if @detailed

        attributes.select do |key, _|
          SPARSE_PREFIXES.any? { |prefix| key.start_with?(prefix) } ||
            SPARSE_ATTRIBUTES.include?(key)
        end
      end
    end
  end
end
```
assistant