The following sources were cited in SAP Digital Futures Issue 05: Bitcoin’s Blockchain – A New Model For Trust

The Bitcoin blockchain — the digital ledger of transactions — is growing exponentially, and doubled to 40GB from August 2014 to August 2015.
Blockchain.info, Blockchain Size graph, https://blockchain.info/charts/blocks-size?timespan=all&showDataPoints=false&daysAverageString=1&show_header=true&scale=0&address=

As of August 2015, the Bitcoin blockchain was already solving nearly 400 billion complex mathematical equations per second.
Blockchain.info, Hash Rate graph, https://blockchain.info/charts/hash-rate

The first worldwide conference on applying blockchain technology was held on May 28, 2015.
The Block Chain Summit, http://www.blockchainsummit.io/

Honduras began creating land titles based on blockchain technology in May 2015.
Gertrude Chavez-Freyfuss, “Honduras to build land title registry using bitcoin technology”, Reuters, May 15th, 2015, http://in.reuters.com/article/2015/05/15/usa-honduras-technology-idINKBN0O01V720150515

Visa, the world’s largest pay­ment network, is launching a blockchain technology development team to bring secure digital finance to unbanked consumers.
Giulio Prisco, “Visa to Deploy Blockchain Research Team in Bangalore, India”, Bitcoin Magazine, August 12th, 2015, https://bitcoinmagazine.com/21547/visa-deploy-blockchain-research-team-bangalore-india/