In the US, the cultivated area (hectares) and production (tonnes) of crops that require or benefit from insect pollination (directly dependent crops: apples, almonds, blueberries, cucurbits, etc.) increased from 1992, the first year in this study, through 1999 and continued near those levels through 2009; aggregate yield (tonnes/hectare) remained unchanged. The value of directly dependent crops attributed to all insect pollination (2009 USD) decreased from $14.29 billion in 1996, the first year for value data in this study, to $10.69 billion in 2001, but increased thereafter, reaching $15.12 billion by 2009.
Links:
[1] http://admin.indiaenvironmentportal.org.in/feature-article/insect-pollinated-crops-insect-pollinators-and-us-agriculture-trend-analysis
[2] http://admin.indiaenvironmentportal.org.in/category/author/nicholas-w-calderone
[3] http://admin.indiaenvironmentportal.org.in/category/journal/plos-one
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/agriculture
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/insects
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/united-states-america-us
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/honey-bees
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/seeds