Please answer the given financial question based on the context.
Context: item 2 . properties our principal offices are located in boston , southborough and woburn , massachusetts ; atlanta , georgia ; cary , north carolina ; mexico city , mexico ; and sao paulo , brazil . details of each of these offices are provided below: .
|location|function|size ( square feet )|property interest|
|boston ma|corporate headquarters us tower division headquarters and american tower international headquarters|19600|leased|
|southborough ma|information technology data center|13900|leased|
|woburn ma|us tower division lease administration site leasing management and broadcast division headquarters|57800|owned ( 1 )|
|atlanta ga|us tower division accounting services headquarters|21400|leased|
|cary north carolina|us tower division new site development site operations and structural engineering services headquarters|17500|leased|
|mexico city mexico|mexico headquarters|11000|leased|
|sao paulo brazil|brazil headquarters|5200|leased|
( 1 ) the facility in woburn contains a total of 163000 square feet of space . approximately 57100 square feet of space is occupied by our lease administration office and our broadcast division , and we lease the remaining space to unaffiliated tenants . in addition to the principal offices set forth above , we maintain 15 regional area offices in the united states through which we operate our tower leasing and services businesses . we believe that our owned and leased facilities are suitable and adequate to meet our anticipated needs . we have also established an office in delhi , india to pursue business opportunities in india and southeast asia , and we have an international business development group based in london , england . our interests in our communications sites are comprised of a variety of ownership interests , including leases created by long-term ground lease agreements , easements , licenses or rights-of-way granted by government entities . pursuant to the loan agreement for the securitization , the tower sites subject to the securitization are subject to mortgages , deeds of trust and deeds to secure the loan . a typical tower site consists of a compound enclosing the tower site , a tower structure , and one or more equipment shelters that house a variety of transmitting , receiving and switching equipment . there are three principal types of towers : guyed , self- supporting lattice , and monopole . 2022 a guyed tower includes a series of cables attaching separate levels of the tower to anchor foundations in the ground . a guyed tower can reach heights of up to 2000 feet . a guyed tower site for a typical broadcast tower can consist of a tract of land of up to 20 acres . 2022 a lattice tower typically tapers from the bottom up and usually has three or four legs . a lattice tower can reach heights of up to 1000 feet . depending on the height of the tower , a lattice tower site for a wireless communications tower can consist of a tract of land of 10000 square feet for a rural site or less than 2500 square feet for a metropolitan site . 2022 a monopole is a tubular structure that is used primarily to address space constraints or aesthetic concerns . monopoles typically have heights ranging from 50 to 200 feet . a monopole tower site of the kind typically used in metropolitan areas for a wireless communications tower can consist of a tract of land of less than 2500 square feet. .
Question: what portion of the woburn property owned by the american tower corporation is subleased?


Answer: The answer is:2e-05