New Delhi, July 30 -- Eight of the 19 industries tracked under India's trial Index of Services Production (ISP) posted double-digit growth in May, while another eight expanded from a year ago, signalling broad-based strength in the formal services economy despite mixed signals from manufacturing and external trade, per data released on Wednesday. The 19 sectors covered now account for about 60% of the services economy. The overall index number will be detailed later after studying stability and resilience of sub-sectoral services, the statistics ministry had said earlier this month while launching the series. "As per the Index of Services Production (ISP), growth of the covered 19 services amounting to 60% of total services output was 9.8% ...