Using the same form for the change in the number of IDUs in Australia as that estimated by Law et al.,142 and adjusting slightly to the magnitude recently estimated by Mathers et al.,132 we assume that the IDU population in Australia has changed as shown below (see the figure change in the estimated number of Australian IDUs).

The number of IDUs in each state and territory has changed over time. We use numerous IDU population indicators to estimate the proportion of all Australian IDUs in each jurisdiction. The indicators we use are proportion of regular heroin users,143 proportion of accidental deaths due to opioids among those aged 15-54 years,144 percentage of Australian population in each state/territory,145 proportion of national syringes distributed in each state, proportion of national HCV diagnoses in each state/territory through NSPs,54, 146 proportion of all sentenced prisoners convicted of possession or use of drugs in each state/territory,147 proportion of pharmacotherapy clients receiving pharmacotherapy treatment,148 proportion of all drugs consumer and provider arrests, 149 and proportion of amphetamine consumer and provider arrests.149 For the Aboriginal and Torres Strait Islander population, the proportion of NSP survey respondents that were Indigenous was used. The average of these indicators for the proportion of all Australian IDUs that are in each jurisdiction is shown below (see the figure proportion of Australian IDUs in each state/territory.

According to the average of these indicators the estimated number of IDUs in Australia, in each state/territory, and in the Indigenous population is shown below (see the figure estimated number of IDUs in each state/territory (log10).

Change in the estimated number of Australian IDUs (1990-2020)

The dashed regions refer to lower and upper bounds of confidence.
Text equivalent below for Change in the estimated number of Australian IDUs (1990-2020)
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Text version of change in the estimated number of Australian IDUs (1990-2020)

Figures in this description are approximate as they have been read from the graph.
  • The estimated number of Australian IDUs increases steadily from 125,000 in 1990 to 260,000 in 2000 before decreasing sharply to 190,000 in 2002, The number of IDUs then decreases slightly to 180,000 in 2005 and remains constant to 2020.

  • The upper confidence level increases steadily from 160,000 in 1990 to 320,000 in 2000 before decreasing sharply to 230,000 in 2002, The upper confidence level then decreases slightly to 220,000 in 2005 and remains constant to 2020.

  • The lower confidence level increases steadily from 75,000 in 1990 to 160,000 in 2000 before decreasing sharply to 120,000 in 2002, The lower confidence level then decreases slightly to 110,000 in 2005 and remains constant to 2020.

Proportion of Australian IDUs in each state/territory (1997-2007)


Text equivalent below for Proportion of Australian IDUs in NSW (1997-2007)Text equivalent below for Proportion of Australian IDUs in VIC (1997-2007)Text equivalent below for Proportion of Australian IDUs in QLD (1997-2007)Text equivalent below for Proportion of Australian IDUs in SA (1997-2007)Text equivalent below for Proportion of Australian IDUs in WA (1997-2007)Top of pageText equivalent below for Proportion of Australian IDUs in TAS (1997-2007)Text equivalent below for Proportion of Australian IDUs in the NT (1997-2007)Text equivalent below for Proportion of Australian IDUs in the ACT (1997-2007)
Text equivalent below for Proportion of Australian IDUs who are Indigenous (1997-2007)

Text version of proportion of Australian IDUs in each state/territory (1997-2007)

Figures in this description are approximate as they have been read from the graph.
NSWVICQLDSAWATASNTACTIndigenous
1997
46%
25%
13%
7%
7%
2%
1%
2.5%
4%
1998
41%
20%
17%
6%
9%
2%
2%
3%
6%
1999
39%
21%
19%
8%
8%
1%
1%
2.5%
7%
2000
38%
21%
18%
8%
8%
1%
1%
3.5%
8%
2001
37%
21%
19%
8%
9.5%
2%
1%
2.5%
7%
2002
35%
22%
20%
8%
9.5%
2.5%
1%
2.5%
7%
2003
33%
23%
26%
7.5%
10%
3%
1%
3%
8%
2004
31%
22%
24%
8.5%
11%
3.5%
1%
2%
8%
2005
32%
22%
22%
8%
10%
3.5%
1%
2%
10%
2006
30%
24%
24%
8%
12%
3%
1%
2.5%
11%
2007
31%
24%
23%
9%
12%
3.5%
1%
2%
11%
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Estimated number of IDUs in each state/territory (log10) (1997-2007)

Text equivalent below for Estimated number of IDUs in each state/territory - log 10 (1997-2007)

Text version of estimated number of IDUs in each state/territory (log10)

Figures in this description are approximate as they have been read from the graph.
  • Australia: The estimated number of IDUs is 200,000 in 1997. It increases to about 250,000 in 2000 before decreasing to about 200,000 in 2007.

  • NSW: The estimated number of IDUs stays at about 100,000 from 1997 to 2000 before decreasing to about 60,000 in 2007.

  • VIC: The estimated number of IDUs is 50,000 in 1997. It then fluctuates slightly around that figure, ending up at around 45,000 in 2007.

  • QLD: The estimated number of IDUs is 26,000 in 1997. It increases to about 45,000 in 1999 and 2000, and fluctuates around that figure through to 2007.

  • SA: The estimated number of IDUs is 13,000 in 1997. It increases to about 20,000 in 2000 and then trends slightly down in a fluctuating manner to 17,000 in 2007.

  • WA: The estimated number of IDUs is about 16,000 in 1997. It increases to about 20,000 in 1998 and remains at roughly that figure through to 2007.

  • TAS: The estimated number of IDUs is 2,800 in 1997. It decreases to about 2,000 in 1999, increases to about 4,000 in 2003, and remains at roughly that level through to 2007.

  • NT: The estimated number of IDUs is about 2,000 in 1997. It increases to 3,500 in 1998, drops back down to 2,000 in 1999, increases to 3,000 in 2001, and then drops again to about 1,000 in 2003. The estimated number then increases to about 2,000 in 2007.

  • ACT: The estimated number of IDUs increases in a fluctuating manner from 3,500 in 1997 to about 7,000 in 2000. It then decreases in a fluctuating manner to about 2,500 in 2007.

  • Indigenous: The estimated number of IDUs is 10,000 in 1997, increases to about 20,000 in 2000, decreases to about 12,000 in 2002 and then increases to about 20,000 in 2007.
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