The inactive telephone lines in telecommunications industry stood at 44,647,096 in the first quarter of the year.
In the monthly Subscriber Data made available of NCC posted on its website, the connected lines as at March was 161,928,765, while the figure of the active numbers was 117,281,669.
The inactive lines were 38,518,699 in the last quarter of 2012.
NCC said that additional 6,128,397 lines were dormant, thus jerking the number to 44.647,096 in March.
The Subscriber Data showed that of the 44,647,096 telephone lines, Global System for Mobile communication (GSM) network had a total of 31,061,267.
Also, the mobile section of the Code Division Multiple Access (CDMA) had a total of 11,544,933 inactive lines, while the Fixed Wired/Wireless network had 2,040,896 dormant lines.
From the 117,281,669 active telephone lines on the operators' networks in the first quarter, the GSM had a share of 114,172,440.
The CDMA had 2,703,604 active lines, while the Fixed Wired/Wireless network had 405,625 subscribers.
The installed capacity in the industry increased by 25,589,978 from 211,808,092 in last quarter of 2012 to 237,397,890 in first quarter of 2013.
The installed capacity refers to the total infrastructure that a network put in place to accommodate a certain number of telephone lines without having congestion or poor network quality.
The GSM networks had an installed capacity of 182,065,415 in the last quarter of 2012, which increased to 207,653,213 in first quarter of 2013.
The CDMA had an installed capacity of 18,400,000 in the first quarter of 2013, unchanged from the figure of last quarter of 2012, while the fixed networks had 11,342,677 lines in last quarter of 2012.
It, however, increased to 11,362,677 in first quarter of 2013.
Teledensity of Nigeria's telecommunications industry climbed to 83.77 per cent in first quarter 2013, compared to 80.85 per cent in the last quarter of 2012.
Teledensity measures the percentage of a country's population that has access to telecommunications services as determined by the subscriber base.
Nigeria's teledensity is currently calculated by NCC on a population of 140 million people.
The data showed that although operators were working aggressively to increase subscriber base, some SIM card holders were not activating the SIM cards they bought.
The increase in the GSM installed capacity showed that the operators' were ready to accommodate more subscribers, even as the CDMA operators had decided to maintain their 18,400,000 capacity.