Table 3.

Duration of consumption (in months) and age (years).

Number of months	Percentage (2000)	Percentage (2010)	Average age (2000)	Average age (2010)
1–3	63.1%	68.8%	70.56%	60.98∗
3–6	11.9%	9.8%	76.11∗	65.79∗
6+	25.0%	21.4%	79.35∗	68.80∗

^∗ p < 0.005 (age between each two groups, for effects of duration of usage within each year and for effect of time within each duration group).