I'm using Stata 14 and need to count the number of observation (conm) per year (srcdate) per company (cnms) . The data is from Compustat Segment database and covers the period 2000 - 2020. The sample data using dataex is:
Can anyone help?
Code:
* Example generated by -dataex-. To install: ssc install dataex clear input str50 cnms int Date str58 conm "A & P" 18627 "KITE REALTY GROUP TRUST" "A & P" 18992 "KITE REALTY GROUP TRUST" "A & P" 19358 "KITE REALTY GROUP TRUST" "A I Credit" 15065 "MTM TECHNOLOGIES INC" "A I Credit" 15430 "MTM TECHNOLOGIES INC" "A I Credit" 14700 "MTM TECHNOLOGIES INC" "A I Credit" 15795 "MTM TECHNOLOGIES INC" "A T & T CORP" 17531 "RURAL CELLULAR CORP -CL A" "A T & T CORP" 14975 "SOAPSTONE NETWORKS INC" "A T & T CORP" 17531 "SOAPSTONE NETWORKS INC" "A T & T CORP" 17531 "TEKELEC" "A T & T CORP" 17166 "SOAPSTONE NETWORKS INC" "A T & T CORP" 17166 "TEKELEC" "A T & T CORP" 17074 "NETOPIA INC" "A T & T Corp" 16801 "SOAPSTONE NETWORKS INC" "A T & T Corp" 15340 "SOAPSTONE NETWORKS INC" "A T & T Corp" 16070 "SOAPSTONE NETWORKS INC" "A T & T Corp" 15705 "SOAPSTONE NETWORKS INC" "A T & T Corp" 16436 "SOAPSTONE NETWORKS INC" "A& P" 17166 "ACADIA REALTY TRUST" "A& P" 17897 "ACADIA REALTY TRUST" "A& P" 16801 "ACADIA REALTY TRUST" "A& P" 17531 "ACADIA REALTY TRUST" "A&D" 14700 "ZONIC CORP" "A&D" 21092 "M/ACOM TECHNOLOGY SOLUTIONS" "A&D" 19996 "M/ACOM TECHNOLOGY SOLUTIONS" "A&D" 18900 "M/ACOM TECHNOLOGY SOLUTIONS" "A&D" 19631 "M/ACOM TECHNOLOGY SOLUTIONS" "A&D" 19266 "M/ACOM TECHNOLOGY SOLUTIONS" "A&D" 20727 "M/ACOM TECHNOLOGY SOLUTIONS" "A&D" 20361 "M/ACOM TECHNOLOGY SOLUTIONS" "A&D.Industrial and TME" 22005 "XILINX INC" "A&J Cheese Company" 14791 "SUPREMA SPECIALTIES INC" "A&J Cheese Company" 15156 "SUPREMA SPECIALTIES INC" "A&M Trading" 19358 "MECHEL PAO" "A&M Trading" 18262 "MECHEL PAO" "A&N Electric Cooperative" 20088 "OLD DOMINION ELECTRIC COOP" "A&N Electric Cooperative" 18627 "OLD DOMINION ELECTRIC COOP" "A&N Electric Cooperative" 21549 "OLD DOMINION ELECTRIC COOP" "A&N Electric Cooperative" 18992 "OLD DOMINION ELECTRIC COOP" "A&N Electric Cooperative" 21184 "OLD DOMINION ELECTRIC COOP" "A&N Electric Cooperative" 20819 "OLD DOMINION ELECTRIC COOP" "A&N Electric Cooperative" 20453 "OLD DOMINION ELECTRIC COOP" "A&N Electric Cooperative" 18262 "OLD DOMINION ELECTRIC COOP" "A&N Electric Cooperative" 19358 "OLD DOMINION ELECTRIC COOP" "A&N Electric Cooperative" 19723 "OLD DOMINION ELECTRIC COOP" "A&N Electric Cooperative" 21914 "OLD DOMINION ELECTRIC COOP" "A&N Electric Cooperative" 17897 "OLD DOMINION ELECTRIC COOP" "A&P" 18262 "ACADIA REALTY TRUST" "A&P" 19358 "ACADIA REALTY TRUST" "A&P" 20088 "ACADIA REALTY TRUST" "A&P" 18992 "ACADIA REALTY TRUST" "A&P" 18627 "ACADIA REALTY TRUST" "A&P" 19723 "ACADIA REALTY TRUST" "A&P Andreou & Paraskevaides Enterprises Ltd" 17166 "KITE REALTY GROUP TRUST" "A&P Supermarkets" 18201 "URSTADT BIDDLE PROPERTIES" "A&P Supermarkets" 19297 "URSTADT BIDDLE PROPERTIES" "A&P Supermarkets" 18931 "URSTADT BIDDLE PROPERTIES" "A&P Supermarkets" 20027 "URSTADT BIDDLE PROPERTIES" "A&P Supermarkets" 17836 "URSTADT BIDDLE PROPERTIES" "A&P Supermarkets" 18566 "URSTADT BIDDLE PROPERTIES" "A&P Supermarkets" 19662 "URSTADT BIDDLE PROPERTIES" "A&P Supermarkets" 20392 "URSTADT BIDDLE PROPERTIES" "A&P/Farmer Jack" 16070 "RPT REALTY" "A&P/Farmer Jack" 15705 "RPT REALTY" "A&P/Farmer Jack" 16436 "RPT REALTY" "A&P/Super Fresh" 17166 "CEDAR REALTY TRUST INC" "A&P/Super Fresh" 16801 "CEDAR REALTY TRUST INC" "A-Mark Precious Metals Inc" 21549 "INCEPTION MINING INC" "A-Mark Precious Metals Inc" 21914 "INCEPTION MINING INC" "A-Mark Precious Metals Inc" 20819 "INCEPTION MINING INC" "A-Mark Precious Metals Inc" 21184 "INCEPTION MINING INC" "A-Max Technology Co Ltd" 17531 "SIGMATEL INC" "A. Lassonde Inc." 19358 "JONES SODA CO" "A. Lassonde Inc." 18627 "JONES SODA CO" "A. Lassonde Inc." 18992 "JONES SODA CO" "A. Lassonde Inc." 18262 "JONES SODA CO" "A. Schulman" 21184 "VENATOR MATERIALS PLC" "A. Schulman" 21549 "VENATOR MATERIALS PLC" "A.L. Kilgo Company, Inc." 21549 "INDSTRL LGST PRPT TRST" "A.L. Kilgo Company, Inc." 21914 "INDSTRL LGST PRPT TRST" "A.L. Kilgo Company, Inc." 21184 "INDSTRL LGST PRPT TRST" "A.P. MOELLER-MAERSK A/S" 18627 "TEXTAINER GROUP HOLDINGS LTD" "A.P. MOELLER-MAERSK A/S" 17166 "TEXTAINER GROUP HOLDINGS LTD" "A.P. MOELLER-MAERSK A/S" 17531 "TEXTAINER GROUP HOLDINGS LTD" "A.P. MOELLER-MAERSK A/S" 17897 "TEXTAINER GROUP HOLDINGS LTD" "A.P. MOELLER-MAERSK A/S" 18262 "TEXTAINER GROUP HOLDINGS LTD" "A.P. Moeller - Maersk A/S" 18992 "ATLAS CORP" "A.P. Moeller - Maersk A/S" 21184 "COSTAMARE INC" "A.P. Moeller - Maersk A/S" 20453 "COSTAMARE INC" "A.P. Moeller - Maersk A/S" 18627 "ATLAS CORP" "A.P. Moeller - Maersk A/S" 21549 "COSTAMARE INC" "A.P. Moeller - Maersk A/S" 20088 "COSTAMARE INC" "A.P. Moeller - Maersk A/S" 18992 "BOX SHIPS INC" "A.P. Moeller - Maersk A/S" 18262 "COSTAMARE INC" "A.P. Moeller - Maersk A/S" 19723 "COSTAMARE INC" "A.P. Moeller - Maersk A/S" 20819 "COSTAMARE INC" "A.P. Moeller - Maersk A/S" 19358 "BOX SHIPS INC" "A.P. Moeller - Maersk A/S" 21914 "COSTAMARE INC" "A.P. Moeller - Maersk A/S" 18627 "PERFORMANCE SHIPPPING INC" end format %td Date
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