In calculating net operating income, vacancy losses must be subtracted from the gross income collected. The normal range for vacancy and collection losses for apartment, office, and retail properties is: between zero and one percent. between one and five percent. between five and fifteen percent. between fifteen and twenty percent. Question 6 (4 points) A tool used by real estate analysts to relate a consumer's activities, interests, opinions, and values to a consumer's demographics is referred to as: geographical information systems (GIS). psychographics. survey research. census mapping