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For optical media, we focused on the three major industry categories: CD audio, CD-ROM, and DVD.


Annual world title production of the 3 media types appears in the following chart. (All figures are rounded to the nearest hundred or terabyte.)

Table 1: Annual world title production of the 3 media types.

Media Type
(Source* & Year Cited)

Unique Items per Year (US)

Unique Items per Year (World)

Conversion Factor

Total Terabytes
(Annual US)

Total Terabytes
(Annual Worldwide)
CD - Music (1998) 33,100 90,000 Uncompressed: .650 GB/item 22 58
Compressed (to MP3): .065 GB/item 2 6
CD- ROM (1999) 500 1,000 Uncompressed (to MP3): .650 GB/item 1 3
Compressed: .065 GB/item .3 .6
DVD-video (1999) 3,000 5,000 4.38 GB/item 13 22
Totals:    Uncompressed 36 83
Compressed 15.3 29
*Detailed source information listed at end of this document.


To estimate how many CD-audio originals are created each year worldwide, we used RIAA statistics regarding the US market share and US record releases (see below). The United States holds a 37% share of the world music market and releases about 33,100 items per year. Therefore, the world produces roughly 90,000 originals per year, equivalent to 58 TB (uncompressed).

Between 1998 and 1999, 1,000 new CD-ROM data titles were added to CD-ROMs in Print, an international directory published by Gale Research. This equals about 3 TB of new information in one year (uncompressed).

The United States currently produces about 60% of the DVD titles available worldwide. Using US title production statistics, we estimate that about 5,000 new DVD titles are produced internationally each year - this is about 22 TB. (Source: Jim Taylor's DVD FAQ).

United States

The US produces approximately 37% of the world's CD-audio titles, 50% of the world's CD-ROM titles and 60% of the world's DVD titles. (Sources: Recording Industry Association of America, International Recording Media Association, and Jim Taylor's DVD FAQ).

The Recording Industry Association of America (RIAA) reports the number of new releases and album re-releases each year. In 1998, 33,100 titles were released, roughly equivalent to 22 TB.

The US share of the CD-ROM replication market is 52%, according to the International Recording Media Association. If we assume that the US holds a similar share of CD-ROM title production, then about 500 titles are produced by the United States each year, equivalent to about 1 TB per year.

For the past three years, new DVD titles have been added at a rate of about 3,000 per year (13 TB per year) --a tremendous rate of content growth, but that's because it is a new medium and a significant amount of legacy content is being converted. This rate should decrease as the medium becomes more well-established. (Source: DVD Entertainment Group)


The All Music Guide (a comprehensive database tool used by industry leaders) reports a total of 523,363 titles (445,735 popular music and 77,628 classical music albums). If each work were stored on a 650 MB CD, this would be equivalent to 340 TB. We can assume that this figure represents the US portion of original works, then extrapolate the world stock to be about 1,400,000 titles. [???]

According to the 1999 edition of CD-ROMs in Print, internationally there are about 16,200 unique CD-ROM titles (about 11 TB)--business applications (such as word processing and spreadsheet packages), games, reference tools, and instructional programs. This figure is consistent with other CD-ROM directories, such as the Multimedia & CD-ROM Directory, which lists 17,000 titles.

The United States produces about two-thirds of the total DVD titles. As of June 2000, there are about 8,500 titles available in the United States, 13,000 worldwide. This is equivalent to 37 TB (US) and 57 TB (world).

Rate of Change

Production of CD-Audio and CD-ROM originals is not increasing dramatically. However, the production of DVD originals is growing at a tremendous rate (about 100% per year), due to the fact that material previously available in another format is being reissued on DVD.




In 1999, there were about 4.7 million audio CDs and 3.6 million CD-ROMs replicated worldwide, according to the International Recording Media Association (IRMA). In addition, in 1999 194 million DVD-Video units, 12 million DVD-ROM units, and 2 million DVD-Audio units were replicated.

A total of 1.583 billion recordable CDs (CD-Rs) were sold around the world in 1999, according to Santa Clara Consulting Group. (Source: News Release, "Record sales drive Memorex up to third in world CD market" Estimates of growth in demand for CD-R vary--one consulting firm projects global demand to reach 4.74 billion in the year 2000, while others project demand to be between 2.5 and 3 billion units. (Photonics Industry & Technology Development Association, cited in


During 1999, according to the Recording Industry Association of America (RIAA), 938.9 million CDs were shipped to retail by U.S. producers. The US has a 37% share of the world's sales, according to the International Federation of the Phonographic Industry (IFPI). Therefore, one can extrapolate that CD shipments worldwide are about 2,500 million units. This is equivalent to 1,625 TB.

According to the DVD Entertainment Group, more than 130 million DVD video movies and music video titles were shipped to retail between spring 1997 (when the format launched) and January 2000. 100 million discs were shipped during 1999 alone.


The stock of audio CDs in the United States can be estimated by summing the CD unit sales since the format became popular. The RIAA only provides statistics going back to 1990 - these 10 years of shipments add up to 6,200 million units, equivalent to about 4,030 TB. Ten years of worldwide shipments are approximately 15.2 billion units, equivalent to 10,937 TB.

Since the format was launched in 1997, more than 1.5 billion DVDs have been replicated worldwide, almost 1 billion in North America alone.

Optical Media Bibliography


Click here to see charts supporting the above estimates, with time-series data.

More Discussion

Click here to read additional discussion of the conversion factors and related issues and to obtain detailed bibliographical information.

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