Annual Reports Title 2023 Annual Report 2022 Annual Report 2021 Annual Report 2020 Annual Report 2019 Annual Report Proxy Materials Filing date View May 12, 2023 View HTML 0000006845-23-000013.pdf 0000006845-23-000013.rtf 0000006845-23-000013.xls May 12, 2023 View HTML 0000006845-23-000011.pdf 0000006845-23-000011.rtf 0000006845-23-000011.xls EX-101.SCH - XBRL TAXONOMY EXTENSION SCHEMA May 09, 2022 View HTML 0001193125-22-145002.pdf 0001193125-22-145002.rtf 0001193125-22-145002.xls May 09, 2022 View HTML 0001193125-22-145015.pdf 0001193125-22-145015.rtf 0001193125-22-145015.xls May 27, 2021 View HTML 0001193125-21-173782.pdf 0001193125-21-173782.rtf 0001193125-21-173782.xls