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Table 1 Changes in characteristics of the Tonga Household Income and Expenditure Survey samples, 2009 to 2015/16

From: Equity of expenditure changes associated with a sweetened-beverage tax in Tonga: repeated cross-sectional household surveys

Characteristic   2009 2015/16 Difference
n % or mean (95% CI) n % or mean (95% CI) [percentage points (95% CI), absolute difference]
Total households Sum 1982 100 1800 100  
Household age composition Adults only 519 26.2 (24.1 to 28.3) 506 28.1 (25.6 to 30.6) 1.9 (−1.3 to 5.2)
Adults & children 1463 73.8 (71.7 to 75.9) 1294 71.9 (69.4 to 74.4)  
Mean age (years)   29.4 (28.7 to 30.1)   31.6 (30.5 to 32.7) 2.2 (0.9 to 3.5)
Mean equivalised household income by income tertile Lowest tertile (T$) 665 3739 (3595 to 3883) 523 4168 (4041 to 4295) 428 (237 to 620)
Middle tertile (T$) 650 8358 (8231 to 8485) 637 8808 (8646 to 8970) 450 (244 to 656)
Highest tertile (T$) 668 21,704 (20,286 to 23,122) 639 21,906 (19,734 to 24,078) 202 (− 2392 to 2796)
Main drinking water source Bottled water 39 2.0 (1.2 to 2.7) 144 8.0 (5.7 to 10.3) 6.0 (3.6 to 8.5)
Tank/other 1943 98.0 (97.3 to 98.8) 1656 92.0 (89.7 to 94.3)  
Island Tongatapu (main island) 1367 69.0 (68.7 to 69.3) 1292 71.8 (70.4 to 73.1) 2.8 (1.4 to 4.1)
Outer island/s 615 31.0 (30.7 to 31.3) 508 28.2 (26.9 to 29.6)  
Household size Mean persons per household   5.2 (5.0 to 5.4)   5.7 (5.5 to 5.9) 0.5 (0.2 to 0.7)
Annual quarter Oct-Dec 474 23.9 (17.3 to 30.5) 595 33.1 (24.2 to 41.9) 9.2 (−1.9 to 20.2)
Jan-Mar 491 24.7 (18.0 to 31.5) 315 17.5 (10.5 to 24.5) −7.3 (− 17.0 to 2.5)
Apr-Jun 529 26.7 (19.9 to 33.5) 427 23.7 (16.2 to 31.2) −3.0 (−13.2 to 7.1)
Jul-Sepa 488 24.6 (17.9 to 31.4) 460 25.5 (17.5 to 33.6) 0.9 (−9.6 to 11.4)
Missing    4 0.2 (0.0 to 0.4)  
Household adult obesity All adults obese 579 32.2 (28.9 to 35.5)  
Mixed 1006 55.9 (52.9 to 58.9)  
No adults obese 207 11.5 (9.5 to 13.6)  
Missing 8 0.4 (0.1 to 0.8)  
Mean BMI (kg/m2)     32.3 (31.9 to 32.6)  
  1. aA further tax increase was introduced at the beginning of July 2016 in the final quarter of the 2015/16 HIES study which started in October 2015. Children were less than 15 years old, and adults were 15 years and older, as categorised in the Tonga HIES survey. All values are survey weighted to be representative of the national Tongan population. Income tertiles were calculated on unweighted data and therefore do not include exactly one-third of households. Source: Tonga Department of Statistics, Household Income and Expenditure Surveys