Before 2013, HUD released individual shapefiles for each CoC instead of one national file. This downloads the individual shapefiles and combines them.
get_pre_2013_shapefiles(year)| year | A numeric with the year of the shapefiles.  | 
    
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A spatial data frame:
coc_number: CoC number
coc_name: CoC name
year: Year
geometry: The CoC's spatial data