Since the 1970s, there has been explosive growth in the lobbying industry, particularly in Washington D.C. By 2011, one estimate of overall lobbying spending nationally was $30+ billion dollars. An estimate of lobbying expenses in the federal arena was $3.5 billion in 2010, while it had been only $1.4 billion in 1998. And there is prodigious data since firms are required to disclose lobbying expenditures on a quarterly basis.
