Pot calling the Kettle black ? Let's look at the statistics from the Interior Minister of Germany for 2016, 2017! Are you siting 2015 before the migrants arrived? 

Interior Minster's own words from their own report!

"The number of suspected crimes by refugees, asylum-seekers and illegal immigrants rose to 174,438 in 2016 — an increase of 52.7 per cent, according to the interior ministry.

“This is not something to gloss over,” Thomas de Maiziere,  the interior minister, said as he presented the figures. “Those who commit serious offences here forfeit their right to stay here.
The proportion of foreign suspects, and migrants in particular, is higher than the average for the general population.
Migrants accounted for 8.6 percent of all crime suspects in Germany in 2016, up from 5.7 percent the previous year.
Crimes motivated by Islamism increased by 13.7 percent, the report showed. 

% of Muslims goes up so does the crime rate, that's the correlation.  Do you know of Rotherham? Madness