Occupancy — Occupancy represents the total number of hotel rooms sold in a given period divided by the total number of rooms available. Occupancy measures the utilization of our hotels' available capacity. We use occupancy to measure demand at a specific hotel or group of hotels in a given period. Additionally, occupancy levels help us determine the achievable ADR levels.
Revenue Per Available Room — RevPAR is the product of ADR and occupancy. RevPAR does not include non-room revenues, such as food and beverage revenue or other revenue. We use RevPAR to identify trend information with respect to room revenues from comparable hotel properties and to evaluate hotel performance on a regional basis.
RevPAR changes that are primarily driven by changes in occupancy have different implications for overall revenues and profitability than the changes that are driven primarily by changes in ADR. For example, an increase in occupancy at a hotel would lead to additional variable operating costs (including housekeeping services, utilities and room supplies) and could also result in an increase in other revenue and other operating expense. Changes in ADR typically have a greater impact on operating margins and profitability as they only have a limited effect on variable operating costs.
ADR, Occupancy and RevPAR are commonly used measures within the lodging industry to evaluate operating performance. RevPAR is an important statistic for monitoring operating performance at the individual hotel property level and across our entire business. We evaluate individual hotel RevPAR performance on an absolute basis with comparisons to budget and prior periods, as well as on a regional and company-wide basis. ADR and RevPAR include only room revenue. Room revenue comprised approximately 83.6% of our total revenues for the year ended December 31, 2018, and it is dictated by demand (as measured by occupancy), pricing (as measured by ADR) and our available supply of hotel rooms.
We also use non-GAAP measures such as FFO, Adjusted FFO, EBITDA, EBITDAre and Adjusted EBITDA to evaluate the operating performance of our business. For a more in depth discussion of the non-GAAP measures, please refer to the "Non-GAAP Financial Measures" section.
Principal Factors Affecting Our Results of Operations
The principal factors affecting our operating results include the overall demand for lodging compared to the supply of available hotel rooms and other lodging options, and the ability of our third-party management companies to increase or maintain revenues while controlling expenses.
Demand — The demand for lodging, especially business travel, generally fluctuates with the overall economy. Historically, periods of declining demand are followed by extended periods of relatively strong demand, which typically occurs during the growth phase of the lodging cycle.
Supply — The development of new hotels is driven largely by construction costs, the availability of financing, the expected performance of existing hotels and other lodging options.
We expect that our ADR, Occupancy and RevPAR performance will be impacted by macroeconomic factors such as regional and local employment growth, government spending, personal income and corporate earnings, office vacancy rates, business relocation decisions, airport activity, business and leisure travel demand, new hotel construction and the pricing strategies of our competitors. In addition, our ADR, Occupancy and RevPAR performance are dependent on the continued success of the Marriott, Hilton, Hyatt and Wyndham hotel brands.
Revenues — Substantially all of our revenues are derived from the operation of hotels. Specifically, our revenues are comprised of:
Room revenue — Occupancy and ADR are the major drivers of room revenue. Room revenue accounts for the majority of our total revenues.
Food and beverage revenue — Occupancy, the nature of the hotel property and the type of customer staying at the hotel are the major drivers of food and beverage revenue (i.e., group business typically generates more food and beverage revenue through catering functions as compared to transient business, which may or may not utilize the hotel's food and beverage outlets).
Other revenue — Occupancy and the nature of the hotel property are the main drivers of other ancillary revenue, such as parking fees, golf, pool and other resort fees, gift shop sales and other guest service fees. Some hotels, due to the limited focus of the services offered and size or space limitations at the hotel, may not have the type of facilities that generate other revenue.