Changes

All columns (variables): * patent_number(varchar(255)) unique identifier for the patent, can contain letters hence varchar* grantdate, (date) date that patent was officially granted* prioritydate, (date) date used to established novelty of an invention in regards to other inventions (source: http://www.bios.net/daisy/patentlens/2343.html)* prioritycountry, (varchar(255)) country used to establish novelty of * prioritypatentnumber, cpcsubgroup, pctpatentnumber, claims, appnum, grantyear, appdate, appyear, nber, uspc, uspc_sub