footnote_code footnote_text 10 The 2012 NAICS conversion changed the GGS scope for this industry. BLS utilized backcasting to make the 2010 and 2011 estimates comparable. See the extended technical note for more detail. 8 Data do not meet BLS disclosure standards. 9 Estimate cannot be created due to the conversion from NAICS 2007 to NAICS 2012.