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Table 6 Changes in beverage expenditure as a proportion of income in Tonga from 2009 to 2015/16

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

Characteristic   Household beverage expenditure as a proportion of equivalised household income (%)
2009 2015/16 Absolute difference Relative change (%) Diff. p-value
Soft drinks (taxed in 2013) Total All 0.39 (0.33 to 0.45) 0.32 (0.23 to 0.42) −0.07 (−0.18 to 0.05) −17.0 (−44.5 to 12.8) 0.267
Age Adults only 0.63 (0.43 to 0.82) 0.51 (0.19 to 0.83) −0.12 (− 0.49 to 0.26) −18.6 (−72.1 to 43.5) 0.544
Adults and children 0.31 (0.26 to 0.35) 0.25 (0.20 to 0.30) −0.05 (− 0.12 to 0.01) − 18.0 (−36.9 to 2.9) 0.103
  p-value    0.752   
Income tertile Lowest 0.54 (0.39 to 0.70) 0.51 (0.25 to 0.76) −0.03 (− 0.33 to 0.26) −6.3 (−56.6 to 52.0) 0.821
Middle 0.34 (0.25 to 0.42) 0.30 (0.17 to 0.42) −0.04 (− 0.19 to 0.11) −11.4 (−51.9 to 35.2) 0.617
Highest 0.29 (0.23 to 0.36) 0.20 (0.16 to 0.24) −0.09 (− 0.17 to − 0.02) −31.5 (− 50.4 to −9.1) 0.017
  p-value    0.712   
Island Outer islands 0.19 (0.14 to 0.24) 0.17 (0.11 to 0.23) −0.02 (− 0.09 to 0.06) −8.9 (−45.2 to 34.3) 0.668
Tongatapu (main island) 0.48 (0.39 to 0.57) 0.38 (0.25 to 0.52) −0.10 (− 0.26 to 0.06) −20.2 (−50.7 to 13.1) 0.240
  p-value    0.379   
Milk Total All 0.23 (0.19 to 0.27) 0.33 (0.28 to 0.38) 0.10 (0.04 to 0.17) 43.2 (12.0 to 79.1) 0.002
Age Adults only 0.32 (0.19 to 0.46) 0.43 (0.30 to 0.55) 0.10 (−0.08 to 0.29) 32.1 (−26.4 to 116.3) 0.264
Adults and children 0.20 (0.17 to 0.23) 0.30 (0.25 to 0.34) 0.10 (0.04 to 0.15) 47.9 (17.3 to 82.1) 0.001
  p-value    0.937   
Income tertile Lowest 0.33 (0.22 to 0.44) 0.42 (0.31 to 0.54) 0.10 (−0.06 to 0.25) 28.9 (−19.6 to 92.3) 0.229
Middle 0.20 (0.16 to 0.24) 0.30 (0.23 to 0.37) 0.10 (0.02 to 0.18) 47.9 (5.1 to 97.6) 0.018
Highest 0.17 (0.14 to 0.20) 0.29 (0.23 to 0.36) 0.13 (0.05 to 0.20) 75.7 (27.1 to 130.3) 0.001
  p-value    0.716   
Island Outer islands 0.14 (0.08 to 0.20) 0.21 (0.17 to 0.25) 0.07 (0.00 to 0.14) 48.7 (−11.8 to 139.3) 0.065
Tongatapu (main island) 0.27 (0.22 to 0.33) 0.38 (0.31 to 0.45) 0.11 (0.02 to 0.19) 39.4 (5.2 to 79.2) 0.014
  p-value    0.498   
Bottled water Total All 0.07 (0.00 to 0.13) 0.23 (0.18 to 0.29) 0.16 (0.08 to 0.25) 234.3 (−63.5 to 1072.1) < 0.001
Age Adults only 0.16 (−0.08 to 0.40) 0.29 (0.18 to 0.41) 0.13 (− 0.14 to 0.40) 80 (644 to − 4542) 0.336
Adults and children 0.04 (0.03 to 0.05) 0.21 (0.16 to 0.25) 0.17 (0.12 to 0.22) 479 (284 to 723) < 0.001
  p-value    0.775   
Income tertile Lowest 0.13 (−0.06 to 0.32) 0.23 (0.15 to 0.32) 0.11 (−0.10 to 0.31) 83 (666 to − 4527) 0.311
Middle 0.03 (0.02 to 0.05) 0.23 (0.12 to 0.35) 0.20 (0.09 to 0.31) 603 (200 to 1166) < 0.001
Highest 0.05 (0.03 to 0.06) 0.22 (0.17 to 0.28) 0.18 (0.12 to 0.23) 397 (217 to 637) < 0.001
p-value    0.495   
Island Outer islands 0.01 (0.00 to 0.01) 0.13 (0.09 to 0.16) 0.12 (0.08 to 0.16) 1962 (− 282 to 9346) < 0.001
Tongatapu (main island) 0.10 (0.00 to 0.19) 0.27 (0.20 to 0.35) 0.17 (0.05 to 0.29) 179 (−81 to 939) 0.004
  p-value    0.397   
  1. Note: See the footnote to Table 3