highly significantP = 0·0020
Stratification by age‐groups (Table 1 ) showed a significant decline by 14·7% (from 54·7% to 40%) in the youngest age‐group (0–9 year, P = 0·0394), a highly significant decline ( P = 0·0020) of 10·3% (from 20·8% to 10·5%) in age‐group 50–79, a non‐significant decline ( P = 0·1797) of 13·6% (from 46·3% to 32·7%) in the oldest age‐group (>80 year), and very modest decline in age‐groups 10–19 (3·5%, from 60·9% to 57·4%; P = 0·5989) and 20–49 (3·7%, from 30·1% to 26·4%; P = 0·3740).