Data Layout for supersic87_7299_06_penmod
(v15)

column 1    	-  4 digit SIC (1987 revision) 
column 2   	-  year
column 3   	-  import penetration = imports/(shipments-exports+imports)

Data Layout for supersic87_7299_06_tf
(v15)

column 1    	-  4 digit SIC (1987 revision) 
column 2   	-  year
column 3   	-  import weighted average tariff (duties/customs value)
column 4   	-  import weighted freight rate (1-cif/fob)


Data Layout for supersic87_7299_06_lwc
(v15)

column 1    	-  4 digit SIC (1987 revision) 
column 2   	-  year
column 3   	-  share of imports from countries with <5% US PCGDP
column 4   	-  share of hs10 products in industry sourced from at least one country with <5% of US PCGDP

Notes
1.  Not all sic's are present.  See notes in text of referenced papers