LookML Dashboard generate ratio

[saleemjaffer]

view: conversations {
  sql_table_name: "PUBLIC"."CONVERSTATIONS"
    ;;

  dimension: conversationId {
    type: string
    sql: ${TABLE}."CONVSERSATIONID" ;;
  }

  dimension: userId {
    type: string
    sql: ${TABLE}."USERID" ;;
  }

  dimension: phrase {
    type: string
    sql: ${TABLE}."PHRASE" ;;
  }

  dimension_group: endtime {
    type: time
    datatype: epoch
    sql: ${TABLE}."ENDTIME"/1000 ;;
  }

  dimension_group: starttime {
    type: time
    datatype: epoch
    sql: ${TABLE}."STARTTIME"/1000 ;;
  }

  dimension: conversationDuration {
    type: number
    sql: ${endtime_raw} - ${starttime_raw}  ;;
   }

  measure: count {
    type: count_distinct
    sql: ${conversationId} ;;
  }
}

Using this view I can create a lookML dashboard to get the total `count` of conversations per `userId`. Let’s call this `count_per_user`.
I can also add a `phrase` filter and get the total `count` per `userId`.  Let’s call this `phrase_count_per_user`.

Is there a way I can get the ratio of `count_per_user` / `phrase_count_per_user` on a looker dashboard using some lookML? I want to enable filters on `userId` and `phrase`.