Changes

::U.S. post code follows the pattern [five digits - four digits]. In this way, U.S. patents can be extracted by searching for post code following these patterns using with regular expression.  ::The state and post code are always together, separated by a space. So we can also extract state information with regular expression.

::The extracted records are stored in table ptoassigneend_missus.  The problem is that the city information extracted is not quite good. It messes up with street names. One approach to increase the accuracy is to list all the possible cities in each country, and then match the address columns to these cities, which is time consuming.