The operation, construction, and demoliton of buildings in San Francisco accounts for 56 percent of total citywide greenhouse-gas emissions.
San Francisco is phasing in an ordinance that requires every commercial building 10,000 square feet and larger to track its' energy use and provide an annual summary to tenants as well as the public. They're also required to get a professional energy audit or a tune-up called retrocommissioning every five years.
In the meantime, the best available ways to tackle this question are to benchmark your building with ENERGY STAR Portfolio Manager, which tracks your progress over time and can compare your building to similar buildings put to similar use in similar circumstances. The same basic information can also plug into Lawrence Berkeley Labs' Energy IQ.
Additional technical resources include California's Commercial energy End-Use Survey (CEUS) as well as the Residential Appliance Saturation Survey.